An adverb of time (/ædvɜ:b əv taɪm/) or temporal adverb (/tempɔ:rəl ædvɜ:b/) is an adverb used to express time.
All English adverbs of time are actually adverbs of indefinite time and express indefinite time, such as "soon", "later", recently, immediately, forthwith etc.
To express definite time we need to use noun phrase adverbials (next week, next year) or prepositional phrase adverbials (e.g. "on Sunday", "at two o'clock"). Though "yesterday", "tomorrow", "tonight" and "today" are traditionally analysed as adverbs, more modern analysis identifies them as nouns or pronouns, specifically deictic temporal pronouns.
They should not be confused with the related adverbs of frequency, which specify frequency rather than time.