oneth

'first', or other ordinal derivatives of 'one', such as hundred-and-oneth or minus-oneth

Soon after the first law of thermodynamics was postulated in the mid nineteenth century, it was realized how the law presupposed a more elementary law, which we now call the zeroth law ... But scientists soon realized how even the zeroth law was too advanced, since it presupposed a yet more elementary law, which explains why the minus-oneth law had to be formulated. —Paul M. S. Monk, 2008. "Laws and the minus-oneth law of thermodynamics", in Physical chemistry: understanding our chemical world, p. 8.

(see table 9.1 with row numbers four, ten, and sixteen terminating respectively at the eleventh, twenty-ninth and forty-oneth place) —A. R. Rajwade, 2001. Convex polyhedra with regularity conditions and Hilbert's third problem, p. 72.

Used at the end of algebraic expressions indicating ordinal position that end in 1, such as (k+1)ᵗʰ

About once a year, and generally after the six o'clock news (query for B.B.C. experts — is the six o'clock public more gullible?) a Very Big Noise has reported that, after the n — nth or n — plus — oneth year of the war, the health of the nation is yet again better than ever.

The attempts, to a mathematician at any rate, are less comprehensible than the n plus oneth dimension, where n is any integer you please.

(in compounds with twenty-, thirty-, forty-, etc.) A fractional part of an integer ending in one

about twenty thirty-oneths in value of such sales being made as hereinafter mentioned to a syndicate of persons in the United Kingdom, about seven thirty-oneths to residents in the United States, and about four thirty-oneths to residents in other European countries and the colonies. —"Brooke & Co. (Limited) v. Commissioners of Inland Revenue". In The Weekly Reporter, vol. XLIV, p. 671, August 15, 1896. Supreme Court of Judicature, House of Lords, London.

An ordinal value that is represented by an expression ending in 1 such as the (n + 1)th.

And then it was found that Dr. Whewell, or, as others asserted, one Dr. Donaldson, of Cambridge, had already responded to a similar challenge with an anticipatory variation of the idea : Youths who would senior wranglers be Must drink the juice distilled from tea, Must burn the midnight oil from month to month, Raising binomials to the n + 1th (n plus oneth).