Learn how to say Synonym correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word synonym:
a word that means the same or nearly the same as another word, such as bucket and pail
a word or phrase used as another name for something, such as Hellene for a Greek
(biology) a taxonomic name that has been superseded or rejected
ˌsynoˈnymic, ˌsynoˈnymical adjective
C16: via Late Latin from Greek sunōnumon, from syn- + onoma name