Late Middle English (in an earlier sense). Partly from Anglo-Norman pais, pas, peies, peis, peiz weight, heaviness, importance, measure of weight, piece of metal used as a standard measure of weight, load, balance (late 12th cent. or earlier; compare Old French peis and Anglo-Norman and Old French, Middle French pois) from classical Latin pēnsum weight, and partly from Anglo-Norman peise, peisse measure of weight, balance (first half of the 12th cent. as peise; compare Old French (Blois) paise and Anglo-Norman and Old French, Middle French poise) from post-classical Latin pensa measure of weight (4th cent.; also as pesa, peisa (frequently 1213–1573 in British sources)), weight, heaviness, use as noun of feminine of past participle of classical Latin pendere to weigh.