Why is the ninth month called September?
1818, "inner court open to the sky," from Spanish patio probably from Old Provençal patu, pati "untilled land, communal pasture," from Latin pactum "agreement" (see pact). Another theory traces the Spanish word to Latin patere "to lie open." Meaning "paved and enclosed terrace beside a building" first recorded 1941. Patio furniture is attested from 1969.