為服務多給的錢
這一群直接就是核心畫面本身：帳單以外、因為服務而付出的錢。差別在於這筆錢是誰決定的。
noun · C1
A small amount of money you give to someone as thanks for a service they did for you, such as serving your food or carrying your bags. You give it on top of what you already owe.
小費
核心畫面
You can think of gratuity as the money that sits on top. The bill settles what was owed; the gratuity is the extra, handed over for the service a person gave you. Its oldest feeling is that it is given freely, not charged — and every later use is that same extra money in a different setting, sometimes with the freedom quietly taken out of it.
gratuity 可以想成「多出來的那一筆錢」。帳單結清的是本來就該付的部分，gratuity 是額外的，為了那個人…更多收起
gratuity 可以想成「多出來的那一筆錢」。帳單結清的是本來就該付的部分，gratuity 是額外的，為了那個人提供的服務而給。這個字最早的味道是「白白送的」，不是人家跟你收的。後面幾個意思，都可以看成同一筆「額外的錢」換了場合、換了規模：有時候換成機關在你離職時一次發給你，有時候「自願」這一層被悄悄拿掉，只剩下好聽的名字。From the word’s history
From Medieval Latin gratuitas, 'a free gift', from Latin gratuitus, 'freely given, free'.
來自中世紀拉丁文 gratuitas（一份免費的禮物），再往前是拉丁文 gratuitus（白白給的）。所以這個字的底色一直是「自願送出」。這也說明了為什麼把一筆強制費用、甚至把賄款叫做 gratuity，聽起來會比較好聽——它借用的正是這層「禮物」的感覺。
Wiktionary etymology supplied in this packet (source_ref kaikki:3f6f69a190036ae4:574602772:16051)
Two branches
離職或退伍時一次領的錢
還是「為了你付出的服務而給的額外的錢」，但服務從一頓飯拉長成好幾年，給的人也從客人換成機關，金額因此整個放大。
noun · C1
A large sum of money that an organization gives someone when they finish their job or their service, especially in the army or the navy. It is paid once, as one whole amount.
退職金；退伍金
原始詞典資料3 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。
gratuitynoun/ɡɹəˈtjuːətɪ/
- 1
An additional payment given freely as thanks for service.
- service gratuity
- cash gratuity
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。