性别 (xìng bié) literally combines 性 (xìng), meaning 'sex' or 'nature', and 别 (bié), meaning 'type' or 'category'. Together, they refer to the social and cultural classification of people as male, female, or other gender identities — distinct from biological sex alone. While often used in official forms, medical contexts, and demographic surveys, 性别 reflects how individuals identify and are recognized in society.

This term appears frequently in everyday settings: government documents, school enrollment forms, hospital intake questionnaires, and online profile setups. Unlike the more biologically focused word 'sex', 性别 carries broader sociocultural weight and is increasingly used in discussions about gender equality, LGBTQ+ rights, and inclusive language in Chinese-speaking communities. It is neutral in register and appropriate for both formal and informal written and spoken contexts.