An adpositional phrase, in linguistics, is a syntactic category that includes prepositional phrases, postpositional phrases, and circumpositional phrases. Adpositional phrases contain an adposition (preposition, postposition, or circumposition) as head and usually a complement such as a noun phrase. Language syntax treats adpositional phrases as units that act as arguments or adjuncts. Prepositional and postpositional phrases differ by the order of the words used. Languages that are primarily head-initial such as English predominantly use prepositional phrases whereas head-final languages predominantly employ postpositional phrases. Many languages have both types, as well as circumpositional phrases.
There are three types of adpositional phrases: prepositional phrases, postpositional phrases, and circumpositional phrases.
The underlined phrases in the following sentences are examples of prepositional phrases in English. The prepositions are in bold:
Prepositional phrases have a preposition as the central element of the phrase, i.e. as the head of the phrase. The remaining part of the phrase is usually followed by modifiers such as a noun, pronoun, gerund, or clause. It's sometimes called the prepositional complement. The object of the preposition will often have more than one modifier.
The object of a prepositional phrase is to function as an adjective or adverb.
Postpositional elements are frequent in head-final languages such as Basque, Estonian, Finnish, Georgian, Korean, Japanese, Hindi, Urdu, Bengali and Tamil. The word or other morpheme that corresponds to an English preposition occurs after its complement, hence the name postposition. The following examples are from Japanese, where the case markers perform a role similar to that of adpositions: