真的切成相等的兩半
這一族最貼近核心畫面：有一個具體的東西被分成兩塊一樣大的部分。
verb · B1
To cut or split something into two pieces of the same size.
對半切
核心畫面
One way to hold this word: a single cut straight down the middle, leaving two pieces of exactly the same size. Everything halve does starts there. Sometimes the cut is real — a knife through a tomato. Sometimes only the number is cut, and what falls away is half the money, half the time, half the crowd. Either way, the word promises the same thing: not just less, but exactly half.
halve 可以想成一刀從正中間切下去，留下大小完全一樣的兩塊。這個字的所有用法都從這一刀開始。有時候刀是真的，切的…更多收起
halve 可以想成一刀從正中間切下去，留下大小完全一樣的兩塊。這個字的所有用法都從這一刀開始。有時候刀是真的，切的是番茄、馬鈴薯、三明治。有時候被切的只是數字，掉下來的那一半是錢、是時間、是人數。不管切的是東西還是數量，這個字答應的都是同一件事：不只是變少，而是剛好一半。也因為這樣，它比 reduce、cut 精確得多。From the word’s history
From Middle English halven, going back through West Germanic to the same root as half. The verb was built straight out of the word for half, which is why it has never meant anything looser than that.
halve 來自中古英文 halven，再往上追到與 half（一半）同一個日耳曼語詞根。這個動詞是直接從「一半」這個字長出來的，所以它從頭到尾只做一件事：把東西弄成一半。這條線索正好解釋了為什麼它比 reduce 或 cut 精確——精確度是它與生俱來的。
Wiktionary entry for halve, etymology_text supplied in this packet (source_ref kaikki:3f6f69a190036ae4:436934084:29437)
Two branches
數量掉到原本的一半
同一刀，但切的是數字。東西沒有真的斷成兩塊，是金額、時間或人數掉到原本的一半。
verb · B2
To bring an amount, a number, a price or a length of time down to half of what it was. It is also used with no object, when the amount itself drops to half.
減半
原始詞典資料5 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。
halveverb/hɑːv/
- 1
To reduce to half the original amount.
- These show that since 1946 the fatality rate in train and movement accidents combined has been halved, [...].
- The difficulty of each puzzle would increase as the number of miners increased, which would keep production to one block of transactions roughly every 10 minutes. In addition, the size of each block bounty would halve every 210,000 blocks—first from 50 bitcoins to 25, then from 25 to 12.5, and so on. Around the year 2140, the currency would reach its preordained limit of 21 million bitcoins.
- 2
To divide into two halves.
- 3
To make up half of.
- So far apart their lives are thrown / From the twin soul that halves their own.
- 4
architectureTo join two pieces of timber etc. by cutting away each for half its thickness at the joining place, and fitting together.
- 5
golfhobbieslifestyleIn match play, to achieve a tie or draw on.
- I, of course, had no difficulty in doing likewise, and we halved the hole; but the awkward fact remained that I must now gain every hole to win the match, for my opponent's score was "nine up," and there only remained ten holes to play.
- All that counts is whether you won, lost, or halved the match.
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。