核心畫面
Picture a list held by someone above you. Your name is read out, and because of that you have to leave your ordinary life and join a bigger group. You did not put your name on the list, and the list is not asking you a question — it is telling you. That one picture covers an army order and a place in the national squad; the only thing that changes is whether you wanted to hear your name.
call-up 可以想成這樣一個畫面：有一份名單握在上面那一方手裡，名單上念到你的名字，你就得離開原本的日子，進到一…更多收起
call-up 可以想成這樣一個畫面：有一份名單握在上面那一方手裡，名單上念到你的名字，你就得離開原本的日子，進到一個更大的組織裡。名單不是你自己填的，你收到的是通知，不是選擇題。有趣的是，軍隊和球隊用的是同一個畫面：一樣是上面點名、一樣是你被叫進隊伍，差別只在於你想不想被點到。From the word’s history
The noun comes straight from the verb phrase call up, meaning to call someone in for service. Turning that action into one thing gives you the order, or the selection, itself.
這個名詞是從動詞片語 call up（把人叫進去服役）直接變過來的。把那個動作整包當成一件事來講，就成了「那道命令」或「那次入選」本身。
Wiktionary entry 'call-up' (kaikki extract supplied in packet): etymology_text 'Deverbal from call up.'