The literary term "monologue" derives from two Greek terms, monos (one) and logos (speech). Thus a monologue is an extended speech by a single character. The term soliloquy is used when a character is alone on stage or appears to be speaking to him or herself rather than to another character. A monologue may be addressed to another character and may not. In other words, all soliloquies are monologues but not all monologues are soliloquies. An example of an important monologue in Julius Caesar is the speech by Marc Antony beginning:
Friends, Romans, countrymen, lend me your ears!
I come to bury Caesar, not to praise him.
which turns the tide of public opinion against the conspirators.