Where does “thirtysomething” come from?

thirtysomething (English) comes from English thirty, from Middle English thirty, from Old English þritig, from Old English þrī, from Proto-West Germanic þrīʀ, from Proto-Germanic þrīz, from Proto-Indo-European *tréyes.

thirtysomething (English): A tricenarian: a person in their thirties, a person aged between 30 and 39 years (inclusive)

Definitions

  1. A tricenarian: a person in their thirties, a person aged between 30 and 39 years (inclusive)

Ancestry of “thirtysomething”, step by step

StepLanguageWordMeaning
1EnglishthirtyThe cardinal number occurring after twenty-nine...
2Middle Englishthirty—
3Old Englishþritigthirty
4Old Englishþrīthree
5Proto-West Germanicþrīʀthree
6Proto-Germanicþrīzthree
7Proto-Indo-European*tréyes—
Every word from Proto-Indo-European *tréyes →Every word from Proto-Germanic þrīz →Every word from Proto-West Germanic þrīʀ →