An adverb is a word or phrase that modifies a verb, adjective, or other adverb by explaining how, when, where, or to what extent an activity takes place. Common adverbs include manner (quickly, softly), time (yesterday, shortly), location (here, everywhere), frequency (often, rarely), and degree (extremely, exceedingly). Although not all adverbs end with "-ly," many do. For example, in the line "She runs quickly," the adverb "quickly" describes her movements. Adverbs improve phrase clarity and precision, making both written and spoken communication more expressive and engaging.