The definition of a synonym is a word that means the same or nearly the same thing as another word.(noun)
An example of synonym is small and little.
See synonym in Webster's New World College Dictionary
Origin: ME sinonyme < L synonymum < Gr synōnymon, of like meaning or like name < syn-, together + onyma, a name
See synonym in American Heritage Dictionary 4
Origin: Middle English sinonyme
Origin: , from Old French synonyme
Origin: , from Latin synōnymum
Origin: , from Greek sunōnumon
Origin: , from neuter of sunōnumos, synonymous; see synonymous.
Learn more about synonym