Thir"ty (?), a. [OE. thritty, AS. þrītig, þrittig; akin to D. dertig, G. dreissig, Icel. þrjātīu, þrjātigi, þrir teger, Goth. þreis tigjus, i.e., three tens. See Three, and Ten, and cf. Thirteen.] Being three times ten; consisting of one more than twenty-nine; twenty and ten; as, the month of June consists of thirty days.

Thir"ty (?), n.; pl. Thirties (&?;). 1. The sum of three tens, or twenty and ten; thirty units or objects.

2. A symbol expressing thirty, as 30, or XXX.

Thir"ty (?), a. [OE. thritty, AS. þrītig, þrittig; akin to D. dertig, G. dreissig, Icel. þrjātīu, þrjātigi, þrir teger, Goth. þreis tigjus, i.e., three tens. See Three, and Ten, and cf. Thirteen.] Being three times ten; consisting of one more than twenty-nine; twenty and ten; as, the month of June consists of thirty days.

Thir"ty (?), n.; pl. Thirties (&?;). 1. The sum of three tens, or twenty and ten; thirty units or objects.

2. A symbol expressing thirty, as 30, or XXX.

• The cardinal number occurring after twenty-nine and before thirty-one, represented in Roman numerals as XXX and in Arabic numerals as 30. Ordinal: thirtieth.