How do I Say and Write
"Thirty" in Japanese?

Pronunciation : Thir"ty
Part of Speech : a.
Etymology : [OE. thritty, AS. ?ritig, ?rittig; akin to D. dertig, G. dreissig, Icel. ?rjatiu, ?rjatigi, ?rir teger, Goth. ?reis tigjus, i.e., three tens. See Three, and Ten, and cf. Thirteen.]
Definition : Defn: Being three times ten; consisting of one more than twenty-nine; twenty and ten; as, the month of June consists of thirty days.
Source : Webster's Unabridged Dictionary, 1913

Pronunciation : Thir"ty
Part of Speech : n.;
Definition : 1. The sum of three tens, or twenty and ten; thirty units or objects.

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

pl. Thirties (.
Source : Webster's Unabridged Dictionary, 1913