In grammar, an adverbial genitive is a noun declined in the genitive case that functions as an adverb.

Adverbial genitives in English

In Old and Middle English, the genitive case was productive, and adverbial genitives were commonplace. While Modern English does not retain the genitive case, it has left various relics, including a number of adverbial genitives. Some of these are now analyzed as ordinary adverbs, including the following:

• always (from all way)
• afterwards, towards, and so on (from their counterparts in -ward, which historically were adjectives)
• once, twice, and thrice (from the roots of one, two, and three)
• hence, thence, and whence (from the roots of here, there, and where)

The adverbial genitive also survives in a number of stock phrases; for example, in "I work days and sleep nights", the words days and nights, while nowadays analyzed as plural nouns, are in fact derived historically from the genitives of day and night. (That they function as adverbs rather than as direct objects is clear from the rephrasing "I work during the day and sleep at night.") The modern British expression "Of an afternoon I go for a walk" has a similar origin, but uses the periphrasis "of noun" to replace the original genitive.

See also

• English grammar
• Genitive case
• History of the English language