1.
younger brother (polite — referring to someone else's)
Polite term for the listener's or a third party's younger brother. The honorific さん makes it appropriate for talking about others; one's own younger brother is 弟 (without さん).
弟さんはおいくつですか。
How old is your younger brother?
弟さんはどんなお仕事をされていますか。
What kind of work does your younger brother do?
先日、田中さんの弟さんと偶然駅でお会いしました。
The other day I happened to run into Mr. Tanaka's younger brother at the station.
Polite reference form for someone else's younger brother — 弟 + the honorific suffix さん. Do not use for one's own younger brother when speaking to outsiders.
USAGE:
- Used when talking about the listener's or a third party's younger brother
- For one's own younger brother (to outsiders): 弟
- Within the family, older siblings call a younger brother by name, not by 弟さん
COMMON COLLOCATIONS:
- 弟さんはおいくつですか: How old is your younger brother?
- 弟さんによろしく: Say hi to your younger brother
- 弟さんとそっくり: looks just like your younger brother
RELATED WORDS:
- 弟: one's own younger brother (humble; for outsiders)
- お兄さん: older brother (polite)
- 妹さん: someone else's younger sister (parallel form)
- 弟さん: even more familiar, used by close friends or to address a child