從頭跑到尾：重點說明
把清單從上跑到下，跑完留下的那份東西就是 rundown。
noun · B2
A short, quick report that gives someone the main points of a situation, a plan, or a set of facts, one after another.
簡要說明
核心畫面
The word is the verb phrase run down turned into a thing. One loose picture holds the family: moving along something from the top to the bottom. Go down a list and you end with a summary; let a business go down and down and you end with a shrinking; chase a runner down between two bases and you end with him caught.
這個字是動詞片語 run down 直接變成的名詞，所以它的畫面也是動作留下來的東西。一種想法是：沿著某樣東西，從頭…更多收起
這個字是動詞片語 run down 直接變成的名詞，所以它的畫面也是動作留下來的東西。一種想法是：沿著某樣東西，從頭一路跑到尾。把一張清單從上跑到下，跑完就是一份重點說明。讓一個廠一年一年往下掉，掉出來的就是規模縮減。在兩個壘之間把跑者追著跑，追到底就是夾殺。三個意思不是三個字，而是同一個「一路跑到底」的動作，落在不同的東西上。From the word’s history
Wiktionary records rundown as a deverbal noun from the phrasal verb run down — the noun is simply the action turned into a thing.
來源記載 rundown 是 run down 這個動詞片語直接轉成的名詞（所謂 deverbal）。也就是說，這個名詞本身就是那個動作被當成一樣東西來講，所以它的每個意思裡都還看得到「跑過去」這個動作。
Wiktionary entries supplied in this packet (kaikki:3f6f69a190036ae4:901901639 and :901910832), etymology_text field: "Deverbal from run down."
Three branches
一路往下掉：規模縮減
同樣是往下走，只是走的不是清單，而是一間公司、一項服務的規模。
noun · B2
The process of gradually making a business, industry or service smaller and less important, or of steadily cutting down the number of things such as ships, trains or staff.
逐步縮減
把人追到底：棒球夾殺
這一支最接近字面：run someone down 就是把人追到底，名詞化之後成了場上的那個畫面。
noun · C1
In baseball, a play in which a runner is caught between two bases while two or more fielders throw the ball to each other and close in until the runner is tagged out.
夾殺