1. large body of salt water; large lake; ocean; large wave. pertaining to a sea, marine; intended for use at sea. seasea , n. [oe. see, as. s&aemacr;; akin to d. zee, os. & ohg. sēo, g. see, ofries. se, dan. s?, sw. sj?, icel. s?r, goth. saiws, and perhaps to l. saevus firce, savage. ? 151 a.]