From The Collaborative International Dictionary of English v.0.48:
Four \Four\, n. 1. The sum of four units; four units or objects. [1913 Webster]
2. A symbol representing four units, as 4 or iv. [1913 Webster]
3. Four things of the same kind, esp. four horses; as, a chariot and four. [1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
Four \Four\ (f[=o]r), a. [OE. four, fower, feower, AS. fe['o]wer; akin to OS. fiwar, D. & G. vier, OHG. fior, Icel. fj[=o]rir, Sw. fyra, Dan. fire, Goth. fidw[=o]r, Russ. chetuire, chetvero, W. pedwar, L. quatuor, Gr. te`ttares, te`ssares, pi`syres, Skr. catur. [root]302. Cf. Farthing, Firkin, Forty, Cater four, Quater-cousin, Quatuor, Quire of paper, tetrarch.] One more than three; twice two. [1913 Webster]