把東西交到對方手上
最貼近字面的一層：手上那樣東西就是真的東西。
noun · B2
The act of giving something to someone, especially something official that has been asked for, or that the other side has a right to have.
交出；移交（物品）
核心畫面
Two pairs of hands, and one thing passing from the first pair to the second. Someone lets go, someone else takes hold, and from that moment the second pair is holding it. What passes can be an object, or control, or the facts you need to do the job. The picture does not change; only the thing in the hands changes.
handover 可以想成兩雙手之間傳過去的一樣東西。一邊放手，一邊接住。從那一刻起，東西就在另一邊了。傳過去的可以…更多收起
handover 可以想成兩雙手之間傳過去的一樣東西。一邊放手，一邊接住。從那一刻起，東西就在另一邊了。傳過去的可以是實體的物品，可以是「誰說了算」，也可以是「你該知道的事」。畫面一直都一樣，只是手上那樣東西換了內容。From the word’s history
The noun comes straight from the verb phrase hand over, so the hands in the picture are written into the word itself.
Wiktionary 記錄 handover 是從動詞片語 hand over 直接變成的名詞。所以「一手交、一手接」不是我們加上去的比喻，它本來就寫在字裡面，也因此還看得到 hand-over 這種寫法。
Wiktionary, packet source_ref kaikki:3f6f69a190036ae4:1432656962:13843 — etymology_text: Deverbal from hand over.
Three branches
交出「誰說了算」
手上那樣東西換成了控制權：不是把物品放進對方手裡，是把決定權放過去。
noun · B2
The act of giving control of a place, a job, or an organization to someone else, so that from that point on they are the one in charge.
（權力、職務的）移交
交出「該知道的事」
這次手上的是資訊：上一班把現在的狀況講給下一班，講完，狀況就由下一班接手。
noun · B2
The information that one person or team passes to the next when they take over the work, for example at the end of a shift.
交班內容；交接資訊