Wiktionary
oneth
a. (label en archaic nonstandard) 'first', or other ordinal derivatives of 'one', such as ''hundred-and-oneth'' or ''minus-oneth'' n. (label en in compounds with ''twenty-, thirty-, forty-'', etc.) A fractional part of an integer ending in one
Usage examples of "oneth".
But the Theniorth need to know, becauthe they’re the oneth who have to make the dethisionth, after all.