# thirtieth

> English word · Adjective · IPA /ˈθɜːti.əθ/ · frequency rank #54,533

## Definitions
1. The ordinal form of the number thirty.

## Etymology
From earlier thirteth, from Middle English thrittithe, threttiþe, thrittyde, from Old English þrītigoþa; equivalent to thirty + -eth. For the modern form, see the etymological notes at twentieth.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/thirtieth