A synonym (also metonym and poecilonym) is a word with the same or similar meaning of another word. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn (σύν) ("with") and onoma (ὄνομα) ("name"). An example of synonyms are the words begin and commence. Likewise, if we talk about a long time or an extended time, long and extended become synonyms. In the figurative sense, two words are often said to be synonymous if they have the same connotation:
...a widespread impression that ... Hollywood was synonymous...