What part of speech is the word "quickly" in the sentence: "She ran quickly to catch the bus"?

In the sentence "She ran quickly to catch the bus," the word "quickly" describes how she ran. It provides more detail about the manner of the action (running), which is a key characteristic of adverbs. Adverbs modify verbs, adjectives, or other adverbs by giving additional information such as how, when, where, or to what extent something is done. In this case, "quickly" modifies the verb "ran," indicating the speed at which the action took place. This aligns perfectly with the function of adverbs in English grammar, confirming that "quickly" is indeed an adverb.