the word is a modern english compound, formed in the late 20th century by combining the cardinal number "thirty," from old english "þrītig," with the indefinite pronoun "something," from old english "sum þing." it was popularized by the title of a 1987 american television drama series about a group of friends in their thirties. the construction follows a productive english pattern of combining a decade number with "something" to denote an approximate age or the demographic cohort of that age range, shifting from a literal description to a cultural label for a life stage.

Structure: thirty + something thirty (old english; cardinal number) + something (old english; indefinite pronoun or thing)