diff --git a/pytchat/tool/download/__init__.py b/pytchat/tool/extract/__init__.py
similarity index 100%
rename from pytchat/tool/download/__init__.py
rename to pytchat/tool/extract/__init__.py
diff --git a/pytchat/tool/download/asyncdl.py b/pytchat/tool/extract/asyncdl.py
similarity index 97%
rename from pytchat/tool/download/asyncdl.py
rename to pytchat/tool/extract/asyncdl.py
index 9d17692..c361754 100644
--- a/pytchat/tool/download/asyncdl.py
+++ b/pytchat/tool/extract/asyncdl.py
@@ -3,7 +3,7 @@ import asyncio
 import json
 from . import parser
 from . block import Block
-from . dlworker import DownloadWorker
+from . worker import ExtractWorker
 from . patch import Patch
 from ... import config 
 from ... paramgen import arcparam
@@ -79,11 +79,11 @@ def ready_blocks(video_id, duration, div, callback):
         _get_blocks(video_id, duration, div, callback))
     return blocks
 
-def download_patch(callback, blocks, video_id):
+def fetch_patch(callback, blocks, video_id):
 
     async def _allocate_workers():
         workers = [
-            DownloadWorker(
+            ExtractWorker(
                 fetch = _fetch,  block = block,
                 blocks = blocks, video_id = video_id
             )
diff --git a/pytchat/tool/download/block.py b/pytchat/tool/extract/block.py
similarity index 87%
rename from pytchat/tool/download/block.py
rename to pytchat/tool/extract/block.py
index 3ca42de..cd854e7 100644
--- a/pytchat/tool/download/block.py
+++ b/pytchat/tool/extract/block.py
@@ -16,9 +16,9 @@ class Block:
         this value increases as fetching chatdata progresses.
 
     end : int :
-        target videoOffsetTimeMs of last chat data for download,
+        target videoOffsetTimeMs of last chat data for extract,
         equals to first videoOffsetTimeMs of next block.
-        when download worker reaches this offset, stop downloading.
+        when extract worker reaches this offset, stop fetching.
 
     continuation : str :
         continuation param of last chat data.
@@ -26,10 +26,10 @@ class Block:
     chat_data : list 
 
     done : bool :
-        whether this block has been downloaded.
+        whether this block has been fetched.
     
     remaining : int :
-        remaining data to download.
+        remaining data to extract.
         equals end - last.
     
     is_last : bool :
diff --git a/pytchat/tool/download/duplcheck.py b/pytchat/tool/extract/duplcheck.py
similarity index 100%
rename from pytchat/tool/download/duplcheck.py
rename to pytchat/tool/extract/duplcheck.py
diff --git a/pytchat/tool/download/downloader.py b/pytchat/tool/extract/extractor.py
similarity index 89%
rename from pytchat/tool/download/downloader.py
rename to pytchat/tool/extract/extractor.py
index 15ab152..a8b5515 100644
--- a/pytchat/tool/download/downloader.py
+++ b/pytchat/tool/extract/extractor.py
@@ -8,7 +8,7 @@ from ... exceptions import InvalidVideoIdException
 logger = config.logger(__name__)
 headers=config.headers
 
-class Downloader:
+class Extractor:
     def __init__(self, video_id, duration, div, callback):
         if not isinstance(div ,int) or div < 1:
             raise ValueError('div must be positive integer.')
@@ -44,7 +44,7 @@ class Downloader:
         return self
 
     def _download_blocks(self):
-        asyncdl.download_patch(self.callback, self.blocks, self.video_id)
+        asyncdl.fetch_patch(self.callback, self.blocks, self.video_id)
         return self
 
     def _remove_duplicate_tail(self):
@@ -57,7 +57,7 @@ class Downloader:
             ret.extend(block.chat_data) 
         return ret
 
-    def download(self):
+    def extract(self):
         return (
             self._ready_blocks()
                 ._remove_duplicate_head()
@@ -68,7 +68,7 @@ class Downloader:
                 ._combine()
         )
 
-def download(video_id, div = 1, callback = None, processor = None):
+def extract(video_id, div = 1, callback = None, processor = None):
     duration = 0
     try:
         duration = VideoInfo(video_id).get("duration")
@@ -77,7 +77,7 @@ def download(video_id, div = 1, callback = None, processor = None):
     if duration == 0:
         print("video is live.")
         return []
-    data = Downloader(video_id, duration, div, callback).download()
+    data = Extractor(video_id, duration, div, callback).extract()
     if processor is None:
         return data
     return processor.process(
diff --git a/pytchat/tool/download/parser.py b/pytchat/tool/extract/parser.py
similarity index 100%
rename from pytchat/tool/download/parser.py
rename to pytchat/tool/extract/parser.py
diff --git a/pytchat/tool/download/patch.py b/pytchat/tool/extract/patch.py
similarity index 96%
rename from pytchat/tool/download/patch.py
rename to pytchat/tool/extract/patch.py
index 2305118..83a2e6d 100644
--- a/pytchat/tool/download/patch.py
+++ b/pytchat/tool/extract/patch.py
@@ -5,7 +5,7 @@ from typing import NamedTuple
 class Patch(NamedTuple):
     """
     Patch represents chunk of chat data
-    which is fetched by asyncdl.download_patch._fetch().
+    which is fetched by asyncdl.fetch_patch._fetch().
     """
     chats : list = []
     continuation : str = None
diff --git a/pytchat/tool/download/dlworker.py b/pytchat/tool/extract/worker.py
similarity index 87%
rename from pytchat/tool/download/dlworker.py
rename to pytchat/tool/extract/worker.py
index 5946bdf..e75a86d 100644
--- a/pytchat/tool/download/dlworker.py
+++ b/pytchat/tool/extract/worker.py
@@ -3,17 +3,17 @@ from . block import Block
 from . patch import Patch, fill, split
 from ... paramgen import arcparam
 
-class DownloadWorker:
+class ExtractWorker:
     """
-    DownloadWorker associates a download session with a block.
+    ExtractWorker associates a download session with a block.
 
-    When the dlworker finishes downloading, the block
-    being downloaded is splitted and assigned the free dlworker.
+    When the worker finishes fetching, the block
+    being fetched is splitted and assigned the free worker.
 
     Parameter
     ----------
     fetch : func :
-        download function of asyncdl
+        extract function of asyncdl
 
     block : Block :
         Block object that includes chat_data
@@ -40,7 +40,7 @@ class DownloadWorker:
             patch = await self.fetch(
                 self.block.continuation, session)
             if patch.continuation is None:
-                """TODO : make the dlworker assigned to the last block
+                """TODO : make the worker assigned to the last block
                 to work more than twice as possible.
                 """
                 break
@@ -50,7 +50,7 @@ class DownloadWorker:
             else:    
                 fill(self.block, patch)
             if self.block.continuation is None:
-                """finished downloading this block """
+                """finished fetching this block """
                 self.block.done = True
                 self.block = _search_new_block(self)
 
diff --git a/pytchat/tool/mining/asyncdl.py b/pytchat/tool/mining/asyncdl.py
index fd62b56..f2211c5 100644
--- a/pytchat/tool/mining/asyncdl.py
+++ b/pytchat/tool/mining/asyncdl.py
@@ -4,7 +4,7 @@ import asyncio
 import json
 from . import parser
 from . block import Block
-from . dlworker import DownloadWorker
+from . worker import ExtractWorker
 from . patch import Patch
 from ... import config 
 from ... paramgen import arcparam_mining as arcparam
@@ -84,11 +84,11 @@ def ready_blocks(video_id, duration, div, callback):
         _get_blocks(video_id, duration, div, callback))
     return blocks
 
-def download_patch(callback, blocks, video_id):
+def fetch_patch(callback, blocks, video_id):
 
     async def _allocate_workers():
         workers = [
-            DownloadWorker(
+            ExtractWorker(
                 fetch = _fetch,  block = block,
                 blocks = blocks, video_id = video_id
             )
diff --git a/pytchat/tool/mining/block.py b/pytchat/tool/mining/block.py
index 9767510..40c95d1 100644
--- a/pytchat/tool/mining/block.py
+++ b/pytchat/tool/mining/block.py
@@ -16,9 +16,9 @@ class Block:
         this value increases as fetching chatdata progresses.
 
     end : int :
-        target videoOffsetTimeMs of last chat data for download,
+        target videoOffsetTimeMs of last chat data for extract,
         equals to first videoOffsetTimeMs of next block.
-        when download worker reaches this offset, stop downloading.
+        when extract worker reaches this offset, stop fetching.
 
     continuation : str :
         continuation param of last chat data.
@@ -26,10 +26,10 @@ class Block:
     chat_data : list 
 
     done : bool :
-        whether this block has been downloaded.
+        whether this block has been fetched.
     
     remaining : int :
-        remaining data to download.
+        remaining data to extract.
         equals end - last.
     
     is_last : bool :
diff --git a/pytchat/tool/mining/patch.py b/pytchat/tool/mining/patch.py
index 186cc82..7666a52 100644
--- a/pytchat/tool/mining/patch.py
+++ b/pytchat/tool/mining/patch.py
@@ -5,7 +5,7 @@ from typing import NamedTuple
 class Patch(NamedTuple):
     """
     Patch represents chunk of chat data
-    which is fetched by asyncdl.download_patch._fetch().
+    which is fetched by asyncdl.fetch_patch._fetch().
     """
     chats : list = []
     continuation : str = None
diff --git a/pytchat/tool/mining/downloader.py b/pytchat/tool/mining/superchat_miner.py
similarity index 87%
rename from pytchat/tool/mining/downloader.py
rename to pytchat/tool/mining/superchat_miner.py
index 0df892b..d6052a8 100644
--- a/pytchat/tool/mining/downloader.py
+++ b/pytchat/tool/mining/superchat_miner.py
@@ -6,7 +6,7 @@ from ... exceptions import InvalidVideoIdException
 logger = config.logger(__name__)
 headers=config.headers
 
-class Downloader:
+class SuperChatMiner:
     def __init__(self, video_id, duration, div, callback):
         if not isinstance(div ,int) or div < 1:
             raise ValueError('div must be positive integer.')
@@ -34,7 +34,7 @@ class Downloader:
         return self
 
     def _download_blocks(self):
-        asyncdl.download_patch(self.callback, self.blocks, self.video_id)
+        asyncdl.fetch_patch(self.callback, self.blocks, self.video_id)
         return self
 
     def _combine(self):
@@ -43,7 +43,7 @@ class Downloader:
             ret.extend(block.chat_data) 
         return ret
 
-    def download(self):
+    def extract(self):
         return (
             self._ready_blocks()
                 ._set_block_end()
@@ -51,7 +51,7 @@ class Downloader:
                 ._combine()
         )
 
-def download(video_id, div = 1, callback = None, processor = None):
+def extract(video_id, div = 1, callback = None, processor = None):
     duration = 0
     try:
         duration = VideoInfo(video_id).get("duration")
@@ -60,7 +60,7 @@ def download(video_id, div = 1, callback = None, processor = None):
     if duration == 0:
         print("video is live.")
         return []
-    data = Downloader(video_id, duration, div, callback).download()
+    data = SuperChatMiner(video_id, duration, div, callback).extract()
     if processor is None:
         return data
     return processor.process(
diff --git a/pytchat/tool/mining/dlworker.py b/pytchat/tool/mining/worker.py
similarity index 80%
rename from pytchat/tool/mining/dlworker.py
rename to pytchat/tool/mining/worker.py
index f7da603..3a53e40 100644
--- a/pytchat/tool/mining/dlworker.py
+++ b/pytchat/tool/mining/worker.py
@@ -3,17 +3,17 @@ from . block import Block
 from . patch import Patch, fill
 from ... paramgen import arcparam
 INTERVAL = 1
-class DownloadWorker:
+class ExtractWorker:
     """
-    DownloadWorker associates a download session with a block.
+    ExtractWorker associates a download session with a block.
 
-    When the dlworker finishes downloading, the block
-    being downloaded is splitted and assigned the free dlworker.
+    When the worker finishes fetching, the block
+    being fetched is splitted and assigned the free worker.
 
     Parameter
     ----------
     fetch : func :
-        download function of asyncdl
+        extract function of asyncdl
 
     block : Block :
         Block object that includes chat_data
diff --git a/pytchat/util/__init__.py b/pytchat/util/__init__.py
index 60be578..9b9d1ab 100644
--- a/pytchat/util/__init__.py
+++ b/pytchat/util/__init__.py
@@ -1,7 +1,7 @@
 import requests,json,datetime
 from .. import config
 
-def download(url):
+def extract(url):
     _session = requests.Session()
     html = _session.get(url, headers=config.headers)
     with open(str(datetime.datetime.now().strftime('%Y-%m-%d %H-%M-%S')
diff --git a/tests/test_dl_asyncdl.py b/tests/test_extract_asyncdl.py
similarity index 93%
rename from tests/test_dl_asyncdl.py
rename to tests/test_extract_asyncdl.py
index c28b327..2cef81b 100644
--- a/tests/test_dl_asyncdl.py
+++ b/tests/test_extract_asyncdl.py
@@ -1,12 +1,12 @@
 import aiohttp
 import asyncio
 import json
-from pytchat.tool.download import parser
+from pytchat.tool.extract import parser
 import sys
 import time
 from aioresponses import aioresponses
 from concurrent.futures import CancelledError
-from pytchat.tool.download import asyncdl
+from pytchat.tool.extract import asyncdl
 
 def _open_file(path):
     with open(path,mode ='r',encoding = 'utf-8') as f:
diff --git a/tests/test_dl_duplcheck.py b/tests/test_extract_duplcheck.py
similarity index 90%
rename from tests/test_dl_duplcheck.py
rename to tests/test_extract_duplcheck.py
index 67fc00c..7984dcc 100644
--- a/tests/test_dl_duplcheck.py
+++ b/tests/test_extract_duplcheck.py
@@ -3,10 +3,10 @@ import asyncio
 import json
 import os, sys
 import time
-from pytchat.tool.download import duplcheck
-from pytchat.tool.download import parser
-from pytchat.tool.download.block import Block
-from pytchat.tool.download.duplcheck import _dump
+from pytchat.tool.extract import duplcheck
+from pytchat.tool.extract import parser
+from pytchat.tool.extract.block import Block
+from pytchat.tool.extract.duplcheck import _dump
 def _open_file(path):
     with open(path,mode ='r',encoding = 'utf-8') as f:
         return f.read()
@@ -23,7 +23,7 @@ def test_overlap():
 
     def load_chatdata(filename):
         return parser.parse(
-            json.loads(_open_file("tests/testdata/dl_duplcheck/overlap/"+filename))
+            json.loads(_open_file("tests/testdata/extarct_duplcheck/overlap/"+filename))
         )[1]
 
     blocks = (
@@ -54,7 +54,7 @@ def test_duplicate_head():
 
     def load_chatdata(filename):
         return parser.parse(
-            json.loads(_open_file("tests/testdata/dl_duplcheck/head/"+filename))
+            json.loads(_open_file("tests/testdata/extarct_duplcheck/head/"+filename))
         )[1]
 
     """
@@ -103,7 +103,7 @@ def test_duplicate_tail():
     """
     def load_chatdata(filename):
         return parser.parse(
-            json.loads(_open_file("tests/testdata/dl_duplcheck/head/"+filename))
+            json.loads(_open_file("tests/testdata/extarct_duplcheck/head/"+filename))
         )[1]
     #chat data offsets are ignored.    
     blocks = (
diff --git a/tests/test_dl_patch.py b/tests/test_extract_patch.py
similarity index 91%
rename from tests/test_dl_patch.py
rename to tests/test_extract_patch.py
index 4f5c208..2766497 100644
--- a/tests/test_dl_patch.py
+++ b/tests/test_extract_patch.py
@@ -4,18 +4,18 @@ import json
 import os, sys
 import time
 from aioresponses import aioresponses
-from pytchat.tool.download import duplcheck
-from pytchat.tool.download import parser
-from pytchat.tool.download.block import Block
-from pytchat.tool.download.patch import Patch, fill, split, set_patch
-from pytchat.tool.download.duplcheck import _dump
+from pytchat.tool.extract import duplcheck
+from pytchat.tool.extract import parser
+from pytchat.tool.extract.block import Block
+from pytchat.tool.extract.patch import Patch, fill, split, set_patch
+from pytchat.tool.extract.duplcheck import _dump
 def _open_file(path):
     with open(path,mode ='r',encoding = 'utf-8') as f:
         return f.read()
 
 def load_chatdata(filename):
         return parser.parse(
-            json.loads(_open_file("tests/testdata/dl_patch/"+filename))
+            json.loads(_open_file("tests/testdata/fetch_patch/"+filename))
         )[1]
 
 
@@ -25,7 +25,7 @@ def test_split_0():
 
     ~~~~~~ before ~~~~~~
 
-     @parent_block  (# = already downloaded)
+     @parent_block  (# = already fetched)
     
      first    last                                     end
        |########----------------------------------------|
@@ -79,11 +79,11 @@ def test_split_1():
     """patch.first <= parent_block.last
 
     While awaiting at run()->asyncdl._fetch()
-    downloading parent_block proceeds, 
+    fetching parent_block proceeds, 
     and parent.block.last exceeds patch.first.
 
     In this case, fetched patch is all discarded,
-    and dlworker searches other processing block again. 
+    and worker searches other processing block again. 
 
     ~~~~~~ before ~~~~~~
 
@@ -135,7 +135,7 @@ def test_split_2():
 
     ~~~~~~ before ~~~~~~
 
-     @parent_block  (# = already downloaded)
+     @parent_block  (# = already fetched)
      first    last                           end (before split)
        |########------------------------------|
     
@@ -163,7 +163,7 @@ def test_split_2():
                           first            last=end |
                             |#################|......   cut extra data.
                                                     ^
-    continuation : None (download complete)
+    continuation : None (extract complete)
 
      @fetched patch                                 
                             |-------- patch --------|
@@ -188,11 +188,11 @@ def test_split_none():
     """patch.last <= parent_block.last
 
     While awaiting at run()->asyncdl._fetch()
-    downloading parent_block proceeds, 
+    fetching parent_block proceeds, 
     and parent.block.last exceeds patch.first.
 
     In this case, fetched patch is all discarded,
-    and dlworker searches other processing block again. 
+    and worker searches other processing block again. 
     
     ~~~~~~ before ~~~~~~
 
diff --git a/tests/testdata/dl_duplcheck/head/dp0-0.json b/tests/testdata/extract_duplcheck/head/dp0-0.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/head/dp0-0.json
rename to tests/testdata/extract_duplcheck/head/dp0-0.json
diff --git a/tests/testdata/dl_duplcheck/head/dp0-1.json b/tests/testdata/extract_duplcheck/head/dp0-1.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/head/dp0-1.json
rename to tests/testdata/extract_duplcheck/head/dp0-1.json
diff --git a/tests/testdata/dl_duplcheck/head/dp0-2.json b/tests/testdata/extract_duplcheck/head/dp0-2.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/head/dp0-2.json
rename to tests/testdata/extract_duplcheck/head/dp0-2.json
diff --git a/tests/testdata/dl_duplcheck/head/dp0-3.json b/tests/testdata/extract_duplcheck/head/dp0-3.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/head/dp0-3.json
rename to tests/testdata/extract_duplcheck/head/dp0-3.json
diff --git a/tests/testdata/dl_duplcheck/head/dp0-4.json b/tests/testdata/extract_duplcheck/head/dp0-4.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/head/dp0-4.json
rename to tests/testdata/extract_duplcheck/head/dp0-4.json
diff --git a/tests/testdata/dl_duplcheck/head/dp0-5.json b/tests/testdata/extract_duplcheck/head/dp0-5.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/head/dp0-5.json
rename to tests/testdata/extract_duplcheck/head/dp0-5.json
diff --git a/tests/testdata/dl_duplcheck/overlap/dp0-0.json b/tests/testdata/extract_duplcheck/overlap/dp0-0.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/overlap/dp0-0.json
rename to tests/testdata/extract_duplcheck/overlap/dp0-0.json
diff --git a/tests/testdata/dl_duplcheck/overlap/dp0-1.json b/tests/testdata/extract_duplcheck/overlap/dp0-1.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/overlap/dp0-1.json
rename to tests/testdata/extract_duplcheck/overlap/dp0-1.json
diff --git a/tests/testdata/dl_duplcheck/overlap/dp0-2.json b/tests/testdata/extract_duplcheck/overlap/dp0-2.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/overlap/dp0-2.json
rename to tests/testdata/extract_duplcheck/overlap/dp0-2.json
diff --git a/tests/testdata/dl_duplcheck/overlap/dp0-3.json b/tests/testdata/extract_duplcheck/overlap/dp0-3.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/overlap/dp0-3.json
rename to tests/testdata/extract_duplcheck/overlap/dp0-3.json
diff --git a/tests/testdata/dl_duplcheck/overlap/dp0-4.json b/tests/testdata/extract_duplcheck/overlap/dp0-4.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/overlap/dp0-4.json
rename to tests/testdata/extract_duplcheck/overlap/dp0-4.json
diff --git a/tests/testdata/dl_duplcheck/overlap/dp0-5.json b/tests/testdata/extract_duplcheck/overlap/dp0-5.json
similarity index 100%
rename from tests/testdata/dl_duplcheck/overlap/dp0-5.json
rename to tests/testdata/extract_duplcheck/overlap/dp0-5.json
diff --git a/tests/testdata/dl_patch/pt0-0.json b/tests/testdata/fetch_patch/pt0-0.json
similarity index 100%
rename from tests/testdata/dl_patch/pt0-0.json
rename to tests/testdata/fetch_patch/pt0-0.json
diff --git a/tests/testdata/dl_patch/pt0-1.json b/tests/testdata/fetch_patch/pt0-1.json
similarity index 100%
rename from tests/testdata/dl_patch/pt0-1.json
rename to tests/testdata/fetch_patch/pt0-1.json
diff --git a/tests/testdata/dl_patch/pt0-3.json b/tests/testdata/fetch_patch/pt0-3.json
similarity index 100%
rename from tests/testdata/dl_patch/pt0-3.json
rename to tests/testdata/fetch_patch/pt0-3.json
diff --git a/tests/testdata/dl_patch/pt0-4.json b/tests/testdata/fetch_patch/pt0-4.json
similarity index 100%
rename from tests/testdata/dl_patch/pt0-4.json
rename to tests/testdata/fetch_patch/pt0-4.json
diff --git a/tests/testdata/dl_patch/pt0-5.json b/tests/testdata/fetch_patch/pt0-5.json
similarity index 100%
rename from tests/testdata/dl_patch/pt0-5.json
rename to tests/testdata/fetch_patch/pt0-5.json