adverb
n.a part of speech that describes or adds information to a verb, an adjective, or another adverb. It usually explains how, when, where, or how often something happens.
n.a part of speech that modifies a verb, an adjective, another adverb, or an entire clause. It typically expresses manner, place, time, frequency, or degree.
“In the sentence "she ran quickly," the word "quickly" is an adverb.”
“When learning English grammar, you will notice that many adverbs of manner end in the letters "ly".”
“The placement of an adverb within a sentence can subtly shift its emphasis, distinguishing a sentence-modifying disjunct from a simple modifier of the verb.”
From French adverbe, from Latin adverbium, from ad- (“to”) + verbum (“word, verb”), so called because it is used to supplement other words. By surface analysis, ad- + verb.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.