A synonym for the word "million" is billion, which is defined as one thousand million. Another synonym is multitude, which refers to a large number of something. Another synonym is plethora, which means an excessive amount of something. A fourth synonym is score, which is used to refer to twenty of something. Another synonym is plethora. A sixth synonym is gazillion, which is an informal term used to refer to an extremely large, indefinite number. Lastly, a seventh synonym is infinity, which is used to represent an uncountable or limitless number. These synonyms can be used interchangeably in order to avoid repetition and enhance the language used in writing or speaking.