1.
younger sister (polite — referring to someone else's)
Polite term for the listener's or a third party's younger sister. The honorific さん makes it appropriate for talking about others; one's own younger sister is 妹 (without さん).
Polite reference form for someone else's younger sister — 妹 + the honorific suffix さん. Do not use for one's own younger sister when speaking to outsiders.
Usage
- Used when talking about the listener's or a third party's younger sister
- For one's own younger sister (to outsiders): 妹
- Within the family, older siblings call a younger sister by name, not by 妹さん
Common collocations
- 妹さんはおいくつですか: How old is your younger sister?
- 妹さんによろしく: Say hi to your younger sister
- 妹さんとよく似ている: looks a lot like your younger sister