(a) Cardinal number as adj.: thirty; ~ daies (winter, yeres, etc.), thirty days (years, etc.); also, for thirty days (years, etc.); a ~ winter, about thirty years; a ~ yer, a thirty-year period; (b) cardinal number as noun: thirty men, years, sinews, cubits, etc.; bi ~ and bi ~, in groups of thirty; (c) the abstract number thirty; withdrauen al the thrities, to subtract thirty as many times as possible; (d) in compound numbers; (e) as ordinal number used adjectively: thirtieth; (f) in place name [see Smith PNElem.2.213].