'Sea lion' definitions:

Definition of 'sea lion'

noun

Any of several large eared seals of the northern Pacific related to fur seals but lacking their valuable coat

From: GCIDE

Sea lion \Sea" li"on\ (Zool.) Any one of several large species of seals of the family Otariidae native of the Pacific Ocean, especially the southern sea lion (Otaria jubata) of the South American coast; the northern sea lion (Eumetopias Stelleri) found from California to Japan; and the black, or California, sea lion (Zalophus Californianus), which is common on the rocks near San Francisco. [1913 Webster]

From: GCIDE

Seal \Seal\ (s[=e]l), n. [OE. sele, AS. seolh; akin to OHG. selah, Dan. sael, Sw. sj[aum]l, Icel. selr.] (Zool.) Any aquatic carnivorous mammal of the families Phocidae and Otariidae. [1913 Webster]
Note: Seals inhabit seacoasts, and are found principally in the higher latitudes of both hemispheres. There are numerous species, bearing such popular names as {sea lion}, sea leopard, sea bear, or ursine seal, fur seal, and sea elephant. The bearded seal (Erignathus barbatus), the hooded seal ({Cystophora cristata}), and the ringed seal (Phoca foetida), are northern species. See also Eared seal, Harp seal, Monk seal, and Fur seal, under Eared, Harp, Monk, and Fur. Seals are much hunted for their skins and fur, and also for their oil, which in some species is very abundant. [1913 Webster]
Harbor seal (Zool.), the common seal (Phoca vitulina). It inhabits both the North Atlantic and the North Pacific Ocean, and often ascends rivers; -- called also {marbled seal}, native seal, river seal, bay seal, {land seal}, sea calf, sea cat, sea dog, dotard, ranger, selchie, tangfish. [1913 Webster]