n. & adj.
--n. (pl. -ies)
1. the product of three and ten.
2 a symbol for this (30, xxx, XXX).
3 (in pl.) the numbers from
30 to 39, esp. the years of a century or of a person's life.
--adj. that amount to thirty.
Phrases and idioms:
thirty-first, -second , etc. the ordinal numbers between thirtieth and fortieth. Thirty-nine Articles the points of doctrine assented to by those taking orders in the Church of England. thirty-one, -two , etc. the cardinal numbers between thirty and forty. thirty-second note esp. US Mus. DEMISEMIQUAVER. thirty-two-mo a book with 32 leaves to the printing-sheet.
Derivatives:
thirtieth adj. & n. thirtyfold adj. & adv.
Etymology: OE thritig (as THREE, -TY(2))