弟 – Kanji Meaning, Reading, and Common Words

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What does 弟 mean in Japanese?

弟 means younger brother, the partner of 兄 (older brother). Japanese marks the age of siblings, so 弟 is specifically a little brother.

The kun’yomi おとうと (otouto) is the everyday word: 弟は高校生です (my younger brother is a high school student). Unlike older siblings, 弟 has no special polite honorific of its own, so 弟さん is used for someone else’s younger brother. The on’yomi テイ appears in formal words such as 義弟 (gitei, younger brother-in-law), and the reading appears loosely in 弟子 (deshi, pupil).

Reading

On’yomi: テイ (tei), ダイ (dai)

Kun’yomi: おとうと (otouto)

Basic Information

Kanji 弟
Meaning younger brother
Stroke Count 7
JLPT Level N4

How to Understand This Kanji

おとうと (otouto) is the plain word for your own younger brother and, being modest already, is used with outsiders. For someone else’s younger brother, add さん: 弟さん. There is no equivalent of お兄さん for younger brothers, because honorifics attach to those senior to you. 兄弟 (kyoudai) again means siblings collectively. Formal compounds include 実弟 (biological younger brother) and 義弟 (younger brother-in-law). A special case is 弟子 (deshi), a pupil or disciple, where 弟 carries the idea of a junior who follows a master.

Common Words

  • 弟（おとうと / otouto） — (my) younger brother
  • 兄弟（きょうだい / kyoudai） — siblings, brothers
  • 弟さん（おとうとさん / otoutosan） — (someone’s) younger brother
  • 実弟（じってい / jittei） — one’s biological younger brother
  • 義弟（ぎてい / gitei） — younger brother-in-law
  • 弟子（でし / deshi） — pupil, disciple, apprentice

Example Sentences

  • 弟は高校生です。

    おとうとはこうこうせいです。 / Otouto wa koukousei desu.

    My younger brother is a high school student.

  • 弟さんはおいくつですか。

    おとうとさんはおいくつですか。 / Otoutosan wa oikutsu desu ka.

    How old is your younger brother?

  • 兄弟でよくサッカーをします。

    きょうだいでよくさっかーをします。 / Kyoudai de yoku sakkaa o shimasu.

    My brothers and I often play soccer.

Related Kanji

  • 兄

    — Older brother — 兄弟 (siblings) = 兄 + 弟; the older-younger pair is the core of sibling vocabulary

  • 妹

    — Younger sister — 弟 and 妹 are the two younger siblings; the younger pair mirrors the older 兄姉

  • 姉

    — Older sister — completing the four-sibling set 兄弟姉妹, in which 弟 is the younger-brother member

When Learners Usually See This Kanji

Keep the pair straight: 兄 (elder) and 弟 (younger). When you mention a brother, decide first whether he is older (兄) or younger (弟). Together they build 兄弟 (kyoudai, siblings).

Note the asymmetry of politeness. Older siblings get honorific forms (お兄さん, お姉さん), but younger siblings do not, because Japanese honorifics point upward in seniority. For your own younger brother say 弟; for another person’s, say 弟さん.

弟子 (deshi) is a useful surprise word: it means a pupil or apprentice under a master, as in 弟子入りする (to become an apprentice). The younger-brother kanji fits because a disciple is like a junior in a family of learning.

Summary

弟 means younger brother (otouto), the counterpart of 兄. It forms 兄弟 (siblings), takes さん for others’ younger brothers, and appears in 弟子 (deshi, pupil). Younger siblings take no honorific of their own.