As noun [remaining uses are adjectival]: (a) the number one, the numerical value of one; also, oneness, unity; (b) a written figure one; (c) the first day of the week or month; on of the clokke, one……
Cardinal number as adj.: (a) two; also, with diminished force in generalizing phrase: a furlong or twin [could also be construed as sense 2.(a)]; (b) double, dual; twofold; of two kinds; having two……
