1175–1225;Middle Englishple, earlier plaid < Old French < early Medieval Latinplacitum law-court, suit, decision, decree, Latin: opinion (literally, that which is pleasing or agreeable), noun use of neuter of past participle of placēre to please
lawsomething alleged or pleaded by or on behalf of a party to legal proceedings in support of his claim or defence
criminal lawthe answer made by an accused to the chargea plea of guilty
(in Scotland and formerly in England) a suit or action at law
an excuse, justification, or pretexthe gave the plea of a previous engagement
Word Origin for plea
C13: from Anglo-Norman plai, from Old French plaid lawsuit, from Medieval Latin placitum court order (literally: what is pleasing), from Latin placēre to please
early 13c., "lawsuit," from Anglo-French plai (late 12c.), Old French plait "lawsuit, decision, decree" (9c.), from Medieval Latin placitum "lawsuit," in classical Latin, "opinion, decree," literally "that which pleases, thing which is agreed upon," properly neuter past participle of placere (see please). Sense development seems to be from "something pleasant," to "something that pleases both sides," to "something that has been decided." Meaning "a pleading, an agreement in a suit" is attested from late 14c. Plea-bargaining is first attested 1963. Common pleas (early 13c.) originally were legal proceedings over which the Crown did not claim exclusive jurisdiction (as distinct from pleas of the Crown); later "actions brought by one subject against another."