Where does “twenty-oneth” come from?

twenty-oneth (English) comes from English -th, from Middle English -eth, from Old English -eþ, from Proto-Germanic -þi, from Proto-Indo-European -ti.

twenty-oneth (English): twenty-first

Definitions

  1. twenty-first

Ancestry of “twenty-oneth”, step by step

StepLanguageWordMeaning
1English-thUsed to form nouns from verbs of action; Used to...
2Middle English-ethUsed to form the third-person singular present...
3Old English-eþThird person singular present indicative ending of class 1 weak verbs
4Proto-Germanic-þi—
5Proto-Indo-European-ti—
Every word from Proto-Indo-European -ti →Every word from English -th →Every word from Middle English -eth →