撐住重量的叉形棍子
這一支就是核心畫面本身，先是那樣東西，然後是那個動作。
noun · B2
One of a pair of long sticks with a support at the top. You put them under your arms and lean on them to walk when your leg or foot is hurt. Usually used in the plural.
拐杖（腋下枴）
核心畫面
You can picture a crutch as a stick that forks at the top, so that a body can rest in the fork and push its weight down through the wood to the ground. Two things sit inside that picture: the weight being handed over, and the fork that receives it. Follow the weight and you get the figurative crutch — the thing you hand your own load to. Follow the fork and you get the British use for the place where the legs meet.
crutch 可以想成一根上端分叉的棍子：身體卡在那個叉口，把重量往下壓，棍子再把重量送到地上。這個畫面裡其實有兩樣…更多收起
crutch 可以想成一根上端分叉的棍子：身體卡在那個叉口，把重量往下壓，棍子再把重量送到地上。這個畫面裡其實有兩樣東西。一樣是「被交出去的重量」，一樣是「接住它的那個叉口」。順著重量走，就得到比喻的用法——你把自己扛不動的那份交給了別的東西。順著叉口走，就得到英式英文拿它指兩腿分開的地方。From the word’s history
Wiktionary traces crutch to Old English cryċċ (“crutch, staff”), from a Proto-Indo-European root meaning “to turn, bend”, so the oldest idea in the word is a stick that bends or forks at the top.
Wiktionary 把 crutch 追到古英語 cryċċ（拐杖、杖），再往上是一個「轉、彎」的古老字根。所以這個字裡最老的想法，就是一根上端彎出去、分出叉口的棍子。這也解釋了為什麼「叉口」這一層在英式用法裡還活著。
Wiktionary (kaikki snapshot 3f6f69a190036ae4, source_ref kaikki:3f6f69a190036ae4:1180404464): “From Middle English crucche, from Old English cryċċ (“crutch, staff”), from Proto-West Germanic *krukkju … from Proto-Indo-European *ger- (“to turn, bend”).”
Three branches
拿來靠的東西（比喻）
把身體的重量換成心裡或工作上的重量，畫面其他部分都沒變：你還是把自己扛不動的那份交給別的東西去撐。
noun · B2
Something or someone you lean on for support, especially something you have come to depend on too much and that is not really good for you.
（不太健康的）依賴、支柱
身體分叉的那個位置（英式）
這一支接的不是「撐住」，而是畫面裡的另一半：那個叉口。
noun · C1
The part of your body where your two legs meet the rest of you. The source marks this use as British English; American English uses crotch here.
（英式）胯下、兩腿分叉處