thirties

This term functions as a collective noun referring to a specific ten-year span. When describing a person's age, it denotes the entire decade from 30 to 39, often used to categorize a life stage or a demographic group. It is typically used with the definite article "the" (e.g., "in the thirties").

When referring to the historical decade (1930–1939), the word carries a strong association with specific global events, such as the Great Depression. In this historical sense, it is almost always preceded by "the" and functions as a singular temporal unit despite its plural form.