An adverb is a word that modifies or describes a verb, an adjective, or another adverb. It often tells us how, when, where, or to what extent something happens. For example, in the sentence "She runs quickly," the adverb "quickly" describes how she runs. Adverbs can make sentences more interesting by providing additional details. Adverbs can also modify adjectives, as in "He is very tall," where "very" enhances the adjective "tall." Some common adverbs include quickly, slowly, happily, and often. By using adverbs, we can create clearer and more vivid descriptions in our writing.