儿子

儿子 (érzi) is the everyday word for 'son' — the male child of one's parents. It's used by everyone, in every register: parents talking about their kid, neighbors asking about your family, in writing, on TV. Two things to know: first, the second syllable 子 is unstressed and pronounced with a neutral tone (zi, not zǐ), like most kinship suffixes in modern Mandarin (儿子, 妻子, 房子). Second, Chinese kinship terms are gender-specific — there's no neutral 'child' that defaults to son the way some English-speaking grandparents might say 'my boy.' If you mean 'child' regardless of gender, the word is 孩子 (háizi). Use 儿子 only when you specifically mean a son. The pair word for daughter is 女儿 (nǚ'ér).

Memory hook: 儿 alone means 'child' and 子 also means 'child' — put two 'child' characters together and you specifically get 'son.'