See Also: thirtieth(dictionary)

thirtieth (iou)



thirtieth adjective & noun (ordinal numeral).
[Old English TritigoTa, TritteogoTa, repl. in Middle English by forms from THIRTY + -TH2. Cf. Old Norse Tritugande, Tritugti.]
A. adjective. Next in order after the twenty-ninth, that is number thirty in a series, (represented by 30th). OE.
thirtieth part arch. = sense B.2 below.
b. noun.
The thirtieth person or thing of a category, series, etc., identified contextually. OE.
Each of thirty equal parts into which something is or may be divided, a fraction which when multiplied by thirty gives one, (= thirtieth part above). E19.
Comb.: Forming compound numerals with multiples of a hundred, as two-hundred-and-thirtieth (230th) etc. and (arch.) with numerals below ten, as five-and-thirtieth etc.