The Meaning of onai-doshi [同い年] In Japanese

同い年
おないどし
Romaji: onai-doshi N4

What does 同い年 mean?

Translation and Meaning

same age, same birth year, peer

Definition

同い年 means a person who is the same age as another, i.e., someone born in the same year.

Type

Noun (名詞)

Stroke Order

Meanings

  • Denotes that two or more people share the same birth year, hence the same age
  • Used to describe a person who is the same age as someone else, typically with の to form 同い年の人
  • Conveys equality in age without implying any formal relationship or hierarchy

Etymology

同い (onai) + 年 (toshi) combine to form onai-doshi, the compound meaning same age; 同い acts as a base meaning same, while 年 supplies the age context; the whole is read onai-doshi

Composition

  • 同: sameness
  • 年: year or age
  • い: adjective-like suffix forming the compound

Usage

Used in casual and neutral contexts to describe peers or to categorize people by age in social settings; typically modifies a following noun with の, as in 同い年の人; focuses on age equality rather than status or relationship.
💡 Tips
Mnemonic: imagine two people with identical birthday candles; the candle’s number marks the same age, helping recall the meaning of onai-doshi.

Variations

  • 同年齢 (どうねんれい) — same age
  • 同年代 (どうねんだい) — same generation
  • 年上 / 年下 (ねんじょう / ねんした) — older or younger

Example Phrases

  • 同い年の友達と 昼に 近所のカフェで 長く 話した。
    onai-doshi no tomodachi to hiru ni kinjo no kafe de nagaku hanashita.
    I talked for a long time with a friend who is the same age at a neighborhood cafe at noon.
    Lista:
    • 同い年 (onai-doshi) – same age
    • の (no) – of
    • 友達 (tomodachi) – friend
    • と (to) – with
    • 昼 (hiru) – noon
    • に (ni) – at
    • 近所 (kinjo) – neighborhood
    • の (no) – of
    • カフェ (kafe) – cafe
    • で (de) – at
    • 長く (nagaku) – long
    • 話した (hanashita) – talked
    Core grammar point: 「同い年」 means ‘same age’; here it functions with the particle の to modify a noun, forming 「同い年の友達」.
同い年