early 14c., "quality of being equal or fair, impartiality in dealing with others," from Old French equite (13c.), from Latin aequitatem (nominative aequitas) "equality, uniformity, conformity, symmetry; fairness, equal rights; kindness, moderation," from aequus "even, just, equal" (see equal, adj.). As the name of a system of law, 1590s, from Roman naturalis aequitas, the general principles of justice which corrected or supplemented the legal codes.