Know how to use "fewer" and "less"? Find out.
late 14c., "evenness of surface, uniformity of size;" c.1400, in reference to amount or number, from Old French equalité (Modern French égalité, which form dates from 17c.), from Latin aequalitatem (nominative aequalitas) "equality, similarity, likeness" (also sometimes with reference to civil rights), from aequalis (see equal). Of privileges, rights, etc., from 1520s.