What type of word is 'happily' classified as?

The word 'happily' is classified as an adverb because it is used to modify verbs, adjectives, or other adverbs by describing how an action is performed. In this case, 'happily' tells us the manner in which someone does something, such as 'She sings happily.' This indicates that the singing is done in a happy manner, showcasing the function of adverbs in providing context about actions. Understanding the role of adverbs can help in composing more descriptive and engaging sentences.