means A large pink-fleshed fish, prized as food, that hatches in freshwater rivers, lives in the sea, and swims back upstream to spawn.

from From Latin 'salmo,' which may be linked to 'salire,' to leap — fitting for a fish famous for hurling itself up rapids — though that connection is uncertain. It reached English through Old French 'saumon,' and for centuries the 'l' was silent (the older spelling 'samoun' shows it); later scholars, fond of tidying English up to look more Latin, re-inserted the 'l' on the page even though most speakers still don't say it.