sea lionTranslate sea lion | into French | into German | into Italian | into Spanish Definition of sea lion noun 1an eared seal occurring mainly on Pacific coasts, the large male of which has a mane on the neck and shoulders. Five genera and species in the family Otariidae 2 Heraldry a mythical beast formed of a lion’s head and foreparts and a fish’s tail. sea lion in other Oxford dictionaries Definition of sea lion in the US English dictionary