Sea Lion, in heraldry, a monster consisting of the head and front limbs of a lion with the tail of a fish

Sea Lion, an animal

Sea Lion is the pseudonym for fiction of the naval author Geoffrey Bennett

Operation Sealion, the planned German invasion of Great Britain during World War II

See Line Woman, a signature song by Nina Simone about an upper class prostitute, from the album Broadway-Blues-Ballads (1964), often mispronounced as Sealion Woman.