Translation guide
The English word 'double' covers many meanings, from 'twice as much' to 'two of something' to 'fold in half'. This guide organizes the most useful Japanese expressions by the intended meaning.
Expressing that an amount, number, or degree is two times the original.
Attaches to numbers or counters to mean 'times'. '2倍' means 'double' or 'twice'. Can also be used with verbs like 倍になる (to become double) or 倍にする (to make double).
This year's sales are double last year's.
My salary doubled.
Explicitly 'two times', often interchangeable with 倍. Slightly more emphatic.
Formal or written term meaning 'to double' or 'increase twofold'. Often used in news or business contexts.
Profits doubled.
Referring to something that has two parts, two layers, or two functions.
Means 'double' in the sense of two layers or two overlapping things. Common in words like 二重まぶた (double eyelid) or 二重構造 (double structure).
To bend something so that one part covers another.
Transitive verb meaning 'to fold'. Often used with 半分に (in half).
Something that is exactly the same as another; a copy.
Noun meaning 'duplicate' or 'reproduction'. Often used for documents, keys, artworks.
A word or phrase that can be understood in two ways.
Literally 'double meaning'. Used to describe ambiguous statements.
In sports, a double can refer to a two-base hit in baseball, or doubles in tennis.
To have a second function or use.
Means 'to serve also as' or 'to double as'. Attach to nouns.
English often uses 'double' as a verb (e.g., 'the number doubled'). In Japanese, use 倍になる (become double) or 倍増する (increase twofold) instead of trying to translate 'double' directly as a verb.
The population doubled.
倍 (bai) alone can mean 'double' or 'times', but it's often used with a number. 二倍 (nibai) explicitly means 'two times'. In many contexts they are interchangeable, but 倍 is more common in casual speech when the number is clear from context.
This room is double the size of that one.
彼は二重まぶただ。
He has double eyelids.
This window is double-glazed.
Loanword from English, used in many compound terms like ダブルベッド (double bed), ダブルス (doubles in tennis), or ダブルチェック (double-check).
I reserved a double bed.
Please double-check it.
Prefix meaning 'both' or 'double', used in words like 両手 (both hands), 両親 (both parents), 両方 (both sides). Not used alone.
Please hold it with both hands.
紙を半分に折ってください。
Please fold the paper in half.
To fold up (e.g., a chair, map, clothes). Implies folding neatly for storage.
That chair can be folded up.
Literally 'to make into a two-fold', meaning to fold in half. More explicit than 折る.
I folded the document in half and put it in the envelope.
I'd like to make a duplicate key.
Loanword for 'copy', very common for photocopies or digital copies.
Please make a copy of this document.
A copy or transcript, often used in formal contexts like '写しを送付する' (send a copy).
I enclose a copy of the receipt.
That word has a double meaning.
A traditional Japanese rhetorical device using a pun or pivot word with two meanings. Not used in everyday speech.
In waka poetry, pivot words are often used.
A double (two-base hit) in baseball.
He hit a double down the left-field line.
Doubles (as opposed to singles) in tennis, badminton, etc.
I have a doubles match tomorrow.
This sofa doubles as a bed.
Literally 'can also be used as'. A more roundabout way to express dual function.
This room can double as a study.