c.1300, "a period of the year," with ref. to weather or work, from O.Fr. seison (Mod.Fr. saison) "a sowing, planting," from L. sationem (nom. satio) "a sowing," from pp. stem of serere "to sow" (see sow). Sense shifted in V.L. from "act of sowing" to "time of sowing." In O.Fr. and O.Prov. this was extended to "season" in general (sowing season being the most important). Seasonable is first recorded c.1380. Season ticket is attested from 1820.
"improve the flavor of by adding spices," c.1300, from O.Fr. assaisoner "to ripen, season," from root of season (n.) on the notion of fruit becoming more palatable as it ripens. Applied to timber by 1540. In 16c., it also meant "to copulate with." Seasoning (n.) is from 1580.