A family name or surname inherited within a family (also called 'myouji' or 'family name'); often contrasted with a given name.
苗字は田中です。
My family name is Tanaka.
日本では結婚すると苗字が変わる場合が多い。
In Japan, it's common for the surname to change after marriage.
役所の書類には苗字と名前を正しく書いてください。
Please write your surname and given name correctly on the government form.