名詞：多出來的那一份
名詞用法直接指著畫面裡「超出那條線的那一截」本身——那堆東西、那筆錢。
surplus (extra amount) · noun · C2
The extra amount of a thing that remains when you already have enough, or more than you can use.
剩餘
核心畫面
One way to picture it: you have poured what you need into the container, and there is still some left over the top of it — the part beyond the line of 'enough'.
需要的份量已經裝滿了，而還有一些留在那條「夠了」的線之上。想像一場活動訂了一百份便當，來了八十人——那多出來的二十份…更多收起
需要的份量已經裝滿了，而還有一些留在那條「夠了」的線之上。想像一場活動訂了一百份便當，來了八十人——那多出來的二十份就是 surplus。重點不在「多」，而在「已經超過需要的那條線」：先有一個需求量作為基準，超出去的那一截才叫 surplus。字面上 sur-（在…之上）+ plus（更多），就是「在需要之上還多出來的」。From the word’s history
From Middle English surplus, from Middle French surplus: sur- "over, above" (Latin super) + plus "more" — literally what is over and above.
經由中古英語 surplus 借自中古法語 surplus：sur-（在上面、超過，來自拉丁 super）+ plus（更多），字面就是「超出去的那些」。這解釋了為什麼 surplus 一定要有一個對照的基準——沒有「需要多少」，就談不上「多出多少」。
Middle English surplus < Middle French surplus, as given in the entry's attested origin note
Two branches
形容詞：超過需要的
形容詞用法不是指那一截東西，而是拿「超出需要」這個位置去描述某個人事物：你在說它站在那條線的外面。
surplus (excess) · adjective · C2
Greater in amount than a person, group, or place needs or can use.
多餘的
原始詞典資料6 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
surplusnoun/ˈsɝˌplʌs/
- 1
That which remains when use or need is satisfied, or when a limit is reached; excess; overplus; overage.
- 2
Specifically, an amount in the public treasury at any time greater than is required for the ordinary purposes of the government.
- 3
lawThe remainder of a fund appropriated for a particular purpose.
- 4
lawassets left after liabilities and debts, including capital stock have been deducted.
surplusadj/ˈsɝˌplʌs/
- 1
Being or constituting a surplus; more than sufficient.
- surplus population
- surplus words
surplusverb/ˈsɝˌplʌs/
- 1
To treat as surplus to requirements; to sell off or dismiss from employment, etc.
- This employee was engaged to direct asphalt plants and inasmuch as the work for which he had been employed was completed, he was surplused and his return travel was approved […]
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。