挑出要的：蒐羅
這一支直接就是核心：手伸進去，把要的那些拿出來。
verb · C1
To collect or pick out pieces of information from many different places, keeping the ones you want.
蒐羅、擷取（從許多來源挑出）
核心畫面
Picture a hand going through a big pile, one item at a time, keeping some and setting others aside. That sorting hand is what the word has always been about: its older French and Latin meant gather, collect, select. Every modern use is that same hand — what changes is which side of the pile matters. Sometimes we follow the things picked out and kept; sometimes we follow the ones picked out and taken away.
可以想成一隻手伸進一大堆東西裡，一件一件看過去，有的留下，有的撥到旁邊。這隻在分類的手，就是這個字從頭到尾在做的事—…更多收起
可以想成一隻手伸進一大堆東西裡，一件一件看過去，有的留下，有的撥到旁邊。這隻在分類的手，就是這個字從頭到尾在做的事——它的古法文和拉丁文祖先，意思正是「收集、聚攏、挑選」。今天的每一種用法都還是這隻手，變的只是我們在看堆的哪一邊：有時候跟著被挑出來留下的那些走，有時候跟著被挑出來、要離開的那些走。From the word’s history
From Middle English cullen, from Old French cuillir ('collect, gather, select'), from Latin colligo ('gather together'). The selecting hand in the modern word is the original meaning, not a later image.
來自中古英文 cullen，再往前是古法文 cuillir（收集、聚攏、挑選），源頭是拉丁文 colligō（聚攏在一起）。所以現在這個字裡那隻在挑的手，本來就是它最早的意思，不是後來才加上去的想像。
Wiktionary (kaikki extract, source_ref kaikki:3f6f69a190036ae4:608991798:23006), 'cull' etymology 1
Two branches
挑掉不要的：把一堆變小
同一隻手、同一個動作，只是這次鏡頭跟著被撥到旁邊的那一堆走。
verb · C1
To kill some of the animals in a group on purpose, usually because the group has grown too large or because people want to stop a disease from spreading.
撲殺（有計畫地宰殺部分動物）