somethingth

"The Emperor Nero," said Janet, "He killed Harry's friend, Seneca [the Younger], in the eighty-somethingth year of his age; an old man, and—hush, grandada!" She could not check him.

1870 September – 1871 November, George Meredith, “Commencement of the Splendours and Perplexities of My Father’s Grand Parade”, in The Adventures of Harry Richmond. […], volume II, London: Smith, Elder & Co., […], published 1871, →OCLC, page 286

A concert was to take place in the great hall of the Institute for some local charity, we believe, but are not sure, at which the élite of Alexandria was expected, and the musical talent was to perform—among others the band of the somethingᵗʰ Regiment. And let us impress on you, reader, that the band of the somethingᵗʰ Regiment was something to be proud of!

1888, R[obert] M[ichael] Ballantyne, “Describes a Few Meetings and Several Surprises”, in Blue Lights: Or Hot Work in the Soudan. […], London: James Nisbet & Co., […], →OCLC, pages 402–403

Alfred Hitchcock, still chipper at 76, is back with his fifty-somethingth picture—even the experts seem to have lost count, and disagree.

1976 April 19, John Simon, “Old Man Out”, in Clay S[chuette] Felker, editor, New York, volume 9, number 6, New York, N.Y.: New York Media, →ISSN, →OCLC, page 84, column 1

The third son of a baron, he trained for a distantly royal personage thirty-somethingth from the throne, a snob-value combination that had brought him Rich's custom in the first place.

1992, Dick Francis, chapter 1, in Driving Force, London: Michael Joseph, →ISBN, page 11

In 1949, a computer programmed by man calculated the first 2035 digits of Pi and found that [William] Shanks had made an error in the 500-somethingth digit of Pi. This rendered all the following digits (almost 200) of Shanks' Pi in error.

2003, Melvin Goldstein, “The Computer”, in Physics Foibles: A Book for Physics, Math and Computer-science Students, Victoria, B.C.: Trafford Publishing, →ISBN, page 10