prepositionadverb

Prepositionadverb is a term used in linguistics to describe a word that can function as either a preposition or an adverb, depending on its syntactic environment. In English, several items are analyzed as preposition-adverbs because they can introduce a noun phrase when they act as prepositions, but may stand alone to modify a verb or the whole clause when they act as adverbs.

As a preposition, a prepositionadverb takes a complement and forms a prepositional phrase. For example, in She walked up the hill, up behaves as a preposition with the noun phrase the hill as its complement. As an adverb, the same word can modify a verb without requiring a following noun phrase, as in The balloon rose up, where up modifies the verb rose and has no object.

As a prepositionadverb, the word may also appear in phrasal-verb or particle-like constructions, where its status can be debated within a given grammar. For instance, back can function as a preposition in He walked back to the car (object: the car), or as an adverb in He looked back (modifying the verb with no complement). Other common candidates include over, away, and around, each with contexts that highlight both adverbial and prepositional uses. The exact classification can vary across grammars and languages, and some items are more clearly adverbial or prepositional in certain analyses.

In usage and teaching, recognizing prepositionadverbs helps explain why some words can link to a noun phrase in one context and stand alone in another. They are a reminder of the fluid boundary between parts of speech in natural language and of the role context plays in syntactic categorization.