Where does “umpteenth” come from?

Umpteenth derives from English umpteen, which combines English umpty with English -þ, ultimately tracing to Proto-Indo-European déḱm̥t meaning ten.

umpteenth (English): Occurring in a relatively large but unspecified...

Definitions

  1. Occurring in a relatively large but unspecified...

Ancestry of “umpteenth”, step by step

StepLanguageWordMeaning
1EnglishumpteenAPI; Relatively large but unspecified in number
2Englishumptyindefinite in number; unspecified
3EnglishUMPInitialism of uridine monophosphate
4EnglishumpireThe official who presides over a tennis game sat...
5Middle EnglishnoumperAn arbitrator; an umpire
6Old Frenchnonperodd number, not even
7Old Frenchperby; equal
8Latinpāreven (of a number)
9Proto-Indo-EuropeanperH-to fly; fore, first; exchange
10Proto-Indo-Europeanper-before, in front; first; to go through
11Proto-Indo-Europeanpr̥tóspassed , crossed
Every word from Proto-Indo-European pr̥tósEvery word from Proto-Indo-European per-Every word from Proto-Indo-European perH-