early 13c., from Anglo-French samoun, Old French salmun (Modern French saumon), from Latin salmonem (nominative salmo) "a salmon," probably originally "leaper," from salire "to leap" (see salient, adj.), though some dismiss this as folk etymology. Another theory traces it to Celtic. Replaced Old English læx, from PIE *lax, the more usual word for the fish (see lox). In reference to a color, from 1786.