Definition - A word that has the same or nearly the same meaning as another word.

1. If two words have exactly the same meaning in all contexts, so much so that they can be used interchangeably, they are called exact synonyms.

Example -
sick and ill

Etymology -
The word derives via Latin from the Greek synonymon, word having the same sense as another (from syn, same + onyma, name).

Oxford English Dictionary -
Its first citation is from about 1450:
"Isidorus … lefte noble werkes … as the books of his Ethimologies, … of the ordre of creatures, sinonymes, and mony oþer þinges."
( Higden (Rolls) VI. 51)

Please comment