Translation guide
This guide explains how to express the concept of 'twin' in Japanese, covering both people and objects, with a focus on natural usage and common pitfalls.
Referring to a twin brother or sister, or the state of being twins.
Describing two identical or closely related objects, such as beds, towers, or engines.
Pattern meaning 'twin [noun]', used for objects that come in identical pairs. Common in names of landmarks or products.
双子の塔
twin towers
この船は双子のエンジンを搭載している。
This ship is equipped with twin engines.
Expressing the idea of two things together, often in abstract or compound terms.
Means 'double' or 'twofold'. Used in words like 二重人格 (split personality) or 二重構造 (dual structure). Not for siblings.
The loanword ツイン is only for objects or hotel rooms. Using it for a twin sibling sounds unnatural. Stick to 双子 for people.
双子 is the everyday word for twins. 双生児 is a formal/medical term, rarely used in conversation. Use 双子 unless you're writing a scientific paper.
She is a twin.
私には双子の兄がいます。
I have a twin older brother.
Specifically 'twin sibling' (brother/s). More explicit than 双子 alone.
彼は双子の兄弟がいる。
He has a twin brother.
Specifically 'twin sisters'. Use when gender is known and relevant.
あの双子の姉妹はとても仲がいい。
Those twin sisters get along very well.
Technical/medical term for 'identical twins'. Not used in everyday conversation.
一卵性双生児は遺伝的に同一です。
Identical twins are genetically identical.
Technical/medical term for 'fraternal twins'.
二卵性双生児は普通の兄弟と同じです。
Fraternal twins are like regular siblings.
Loanword from English, often used in product names or hotel rooms (e.g., twin room). Not used for people.
ツインベッドの部屋を予約しました。
I booked a room with twin beds.
Means 'twin-engine' (literally 'double launch'), used in aviation or automotive contexts.
双発機
twin-engine aircraft
その計画には二重の目的がある。
The plan has a twin purpose.