Thirty (?), 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.
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