Definition from Wiktionary, the free dictionary
- 1884, Selections from the Satires of Juvenal: To which is Added the Fifth Satire of Persius, page 144, Eldredge & Brother
- Macleane explains himself very well when he says that “Whath part?” would express quota pars, if we could coin an interrogative adjective after the analogy of the seventh part, eighth, etc.
- 1885, Georg Friedrich Schömann (translator), Marcus Tullius Ciceronis (author), De Natura Deorum: Libri Tres, footnote 79, page 212, Ginn & Heath
- quotus . . . quis-que, “the whatth one,” as we say “every tenth one, hundredth one”
- 1916-1935, Justice Holmes or Harold J. Laski, Holmes-Laski Letters (1953), Mark DeWolfe Howe (editor), page 614, Harvard University Press
- Also for the heaven knows whatth time Maitland’s Life of Leslie Stephen.
- 1939 January-June, Scribner’s Magazine, volume 3, page 302, Charles Scribners Sons
- Hail, dear old story, in coming to thee again for I know not the whatth time!
- 1996 March, Constantin Dumitrescu and V. Seleacu, The Smarandache Function, page 111, Erhus University Press
- Namely, for whath triplets...of positive integers the Smarandache function verifies a Fibonacci-like equality
- 1996 September 4, Jim Farrell, “Blue eyes cryin' in the rain”, bit.listserv.words-l, Usenet
- It'sometimes [sic.] amusing, sometimes, well, just majestic, especially King George the whath, E. Rex's father.
- 1996 October 7, Christian Alice Scarborough, “command not found : help!”, alt.sysadmin.recovery, Usenet
- So I ask him, if the result of your subtraction, converted to decimal, is 21, then that represents the whatth letter of the alphabet?
- 1998 November 11, Paine Ellsworth, “Why all the flames lately?”, alt.writing, Usenet
- Bill Gates the thirty-WHATTH?
- 2005 October 2, Chuck Masterson, “The Suspense”, Chuck Masterson's Actual Blog, at chuckmasterson.blogspot.com 
- we'll be kept idling and warming up until the first competition, which is on the Whatth of Whentember.
- 2006 October 7, Jane M. Wilson, “A Prayer for Paris Hilton”, secret storm's secret site, at secretstorm.blogspot.com 
- But right now I’m re-reading one my most re-read reads, A Prayer for Owen Meany, for the I-don’t-know-whatth time.
which ordinal number