在旁邊等著上場
這一支就是那個舞台側邊的姿勢本身：準備好了、還沒上場、被叫到就能動。人和機器都可以擺這個姿勢。
noun · B2
If people or things are on standby, they are ready and waiting so that they can act, or be used, the moment they are needed.
待命
核心畫面
standby comes straight out of stand by — to stand beside a thing instead of inside it. One way to hold it: a person waiting in the wings of a stage. Not performing, and not gone home. Dressed, in place, watching, able to walk on the second someone calls. Everything the word does is a version of that pose: a nurse waiting for the phone, a passenger waiting for a seat, a tin of milk waiting in the , a television waiting behind its little red light.
standby 可以想成一個人站在舞台側邊等著上場。他沒有在演，可是也沒有回家。衣服穿好了、位置站好了、眼睛盯著台上…更多收起
standby 可以想成一個人站在舞台側邊等著上場。他沒有在演，可是也沒有回家。衣服穿好了、位置站好了、眼睛盯著台上，有人喊一聲就能走出去。這個字的各種用法，都像是同一個姿勢的不同版本：等電話的護理師、等空位的旅客、放在櫃子裡等著頂上的那罐奶粉、亮著小紅燈等人按遙控器的電視。From the word’s history
Wiktionary records standby as a deverbal noun formed from the phrasal verb stand by — the noun is the act of standing by, frozen into a thing. That literal picture of standing beside is still doing the work in every modern use.
Wiktionary 的 standby 條目寫 Deverbal from stand by，也就是這個名詞是直接從動詞片語 stand by 變來的：把「站在旁邊」這個動作凍成一個東西。今天所有的用法，底下都還是那個站在旁邊的畫面。
Wiktionary (kaikki extract kaikki:3f6f69a190036ae4:741028534), standby noun, etymology field: Deverbal from stand by.
Three branches
排隊等別人放掉的位子
一樣站在旁邊等，但等的東西換了：不是等事情發生，而是等一個空出來的位子。
noun · B2
If you are on standby, your name is on a list of people who may be given a seat or a place, but only if one is still free at the last minute.
候補
放在旁邊備著的那一個
站在旁邊的不再是人，而是一樣東西：它不是你第一個會用的，但它一直在那裡等著被用到。
noun · B2
Something you keep ready so that you can use it when you need it, especially when the thing you normally use is not there or does not work.
備用的東西；備案