适龄 (shì líng) is an adjective meaning 'of appropriate age'—typically referring to the age at which someone meets official or societal requirements for a particular activity, such as starting school, getting married, or receiving certain medical services. The character 适 means 'suitable' or 'appropriate', and 龄 means 'age' or 'years of age'; together they form a compound describing age-based eligibility.

This term is commonly used in formal, administrative, and educational contexts—for example, in government documents, school enrollment notices, or public health campaigns. It often appears in phrases like 适龄儿童 (shì líng ér tóng, 'school-age children') or 适龄婚育 (shì líng hūn yù, 'marriage and childbearing at the appropriate age'). While it carries a neutral, factual tone, it can sometimes imply social expectation or policy compliance, so context matters for nuance.