Extra is a word that can be used as an adjective, a noun, or an adverb. As an adjective, it means more than or beyond what is usual, expected, or necessary. As a noun, it means something that is added when you pay for goods or a service, or a person in a movie who does not have a speaking part. As an adverb, it means extremely or excessively. ^{dictionary.com 1 2 3 4}