Translation guide
The English word 'half' can refer to a 50% portion, a midpoint, or partial states. In Japanese, the most common equivalent is 半分 (はんぶん), but other expressions like 半 (はん) as a prefix, 半数 (はんすう) for 'half the number', and idiomatic phrases are used depending on context.
Expressing exactly one of two equal parts of something.
The most common and versatile word for 'half'. Can be used for physical objects, abstract quantities, time, etc.
ケーキを半分に切ってください。
Please cut the cake in half.
仕事の半分は終わった。
Half of the work is done.
Attaches to nouns to mean 'half-', often in fixed compounds. Not freely productive.
Used specifically for 'half the number' of people or countable items.
クラスの半数が賛成した。
Half the class agreed.
Referring to the middle point of a period, distance, or process.
Means 'middle' or 'center', often used for spatial midpoints. Can imply 'halfway' in context.
道の真ん中で止まらないで。
Don't stop in the middle of the road.
Means 'on the way' or 'midway', often for processes or journeys.
Literary or formal word for 'middle' or 'halfway', often used in temporal or abstract contexts.
Describing something that is not fully realized or only partly done.
Used in compounds to mean 'semi-', 'partly', or 'half-'. Common in words like 半透明 (translucent) or 半信半疑 (half in doubt).
半透明のガラス
translucent glass (half-transparent)
半信半疑で話を聞いた。
I listened to the story half in doubt.
Means 'half-finished', 'half-hearted', or 'neither one thing nor the other'. Often negative.
中途半端な態度はやめて。
Stop being so half-hearted.
Expressing 'half' in numerical or fractional contexts.
The standard fractional expression for 'one half'.
その確率は二分の一です。
The probability is one half.
Used after numbers to mean 'and a half'. E.g., 三時半 (3:30), 一か月半 (one and a half months).
三時半に会いましょう。
Let's meet at half past three.
一か月半かかった。
It took a month and a half.
半分 means a 50% portion, not a midpoint in a journey or process. Use 途中 or 真ん中 for spatial/temporal midpoints.
半分 is for portions of a whole (mass, volume, abstract). 半数 is specifically for half of a countable number of people or things.
参加者の半数が女性だった。
Half of the participants were women.
ケーキの半分を食べた。
I ate half of the cake.
彼の言ったことの半分しかわからなかった。
I only understood half of what he said.
割り勘にした。
We split the bill in half.
Natural Japanese uses 割り勘 (splitting evenly), not a literal 'half'.
I fell asleep halfway through the movie.
人生の半ばで転職した。
I changed careers in the middle of my life.