In grammar, the main function of an adjective is to describe a noun, this means adjective say how an animal, person, place, etc. is. Examples of adjectives include words such as blue, big, slow or angry. In the case of the sentence "Shelly and her beautiful dance thoroughly captivated the audience" the word in italics "beautiful" is an adjective because this word describes or modifies the noun "dance" by explaining Shelly's dance was aesthetically pleasing.
