Translation guide
The English word 'doubling' can refer to making something twice as much, folding something in two, or having a dual purpose. This guide covers natural Japanese expressions for these core meanings.
Please double my salary.
A more formal or written term meaning 'to double' or 'to increase twofold'. Often used in news or business contexts.
利益が倍増した。
Profits doubled.
Intransitive version meaning 'to become double'. Use when the subject itself doubles.
人口が二倍になった。
The population doubled.
To bend or fold something so that one part covers the other, often making it half the size.
General verb for folding something like paper, cloth, or a thin object. Often used with '二つに' (in two).
紙を二つに折ってください。
Please fold the paper in half.
Specifically means to fold something up compactly, like a map, chair, or clothes. Implies a neat, compact fold.
Literally 'to make into a two-fold'. Used for folding something exactly in half, like a letter or a sheet.
手紙を二つ折りにした。
I folded the letter in half.
When something serves two roles or is used for two different things at the same time.
Pattern meaning 'to serve also as' or 'to double as'. Attach to a noun. Very common for dual-purpose items or roles.
この部屋は書斎を兼ねている。
This room doubles as a study.
彼は監督と選手を兼ねている。
He doubles as manager and player.
Idiomatic phrase meaning 'to play two roles' or 'to double up on duties'. Often used for people taking on multiple responsibilities.
彼女は秘書と会計の二役をこなしている。
She doubles as a secretary and accountant.
To turn around and go back in the direction one came from, often suddenly.
Standard verb for turning back or retracing one's steps. Used for journeys, walks, etc.
途中で引き返した。
I doubled back halfway.
Literally 'to return along the road one came'. Emphasizes retracing the exact path.
来た道を戻って駅まで行った。
I doubled back to the station.
倍にする is the everyday expression for 'to double' something. 倍増する is more formal and often used in economic or statistical contexts. For casual speech, stick with 倍にする.
English often uses the gerund 'doubling' as a noun (e.g., 'the doubling of prices'). In Japanese, it's more natural to rephrase using verbs like 倍になる or 倍にする, or use noun phrases like 倍増.
人口が倍増したことで住宅問題が起きた。
The doubling of the population caused housing problems.
彼はわずか一年で投資額を倍にした。
He doubled his investment in just one year.
地図を折りたたんだ。
I folded up the map.