弟おとうとさんMeanings1nounyounger brother (honorific)honorific or respectful (sonkeigo)Polite way to refer to someone else's younger brother. Not used for one's own brother.弟おとうとさんはおいくつですか。How old is your younger brother?弟おとうとさんによろしくお伝つたえください。Please give my regards to your younger brother.
