1A male child in relation to his parents; son.
うちの息子は来年中学生になります。
Our son will become a junior high school student next year.
息子に大学の受験勉強を手伝ってもらった。
My son helped me with my university entrance exam studies.
彼は一人息子なので、両親が心配している。
He is an only son, so his parents are worried.
近所の息子さんは礼儀正しくて評判がいい。
The neighbor's son is well-mannered and has a good reputation.
2A colloquial, euphemistic slang term for the penis (informal, spoken usage).