Quickly is an adverb describing how they are running.
The definition of an adverb is a part of speech that provides a greater description to a verb, adjective, another adverb, a phrase, a clause or a sentence.
Beautifully, quickly and happily are each an example of an adverb.
any of a class of words used generally to modify a verb, an adjective, another adverb, a phrase, or a clause, by expressing time, place, manner, degree, cause, etc.: English adverbs often end in -ly (Ex.: fast, carefully, then)
Origin of adverbMiddle English adverbe ; from Classical Latin adverbium ; from ad-, to + verbum, a word
- The part of speech that modifies a verb, an adjective, another adverb, or an entire clause or sentence.
- Any of the words belonging to this part of speech, such as so, very, and rapidly.
Origin of adverbMiddle English adverbe, from Old French, from Latin adverbium (translation of Greek epirrh&emacron;ma) : ad-, in relation to; see ad– + verbum, word, verb; see wer-5 in Indo-European roots.
- Adverbs comprise a fundamental category of words in most languages. In English, adverbs are typically formed from adjectives by appending -ly and are used to modify verbs, verb phrases, adjectives, other adverbs, and entire sentences, but not nouns or noun phrases.