Prepositions are a funny beast. At first, they’re hard to pin down, as apparently different types of words are classed as prepositions. To complicate things further, their effect in a sentence can vary, depending on the context.

The grammatical theory behind prepositions seems complicated at first, but once the concept is grasped, it is actually quite simple. This breakdown should clear everything up and have you purposefully prepositioning in no time.

The secret to understanding prepositions is in the word itself. Preposition: they indicate the position of something or someone, relative to something else.

Examples include: in, on, above, underneath, through, across, with, near, between.  

Interestingly, prepositions are known as a “closed” word class. Unlike nouns and verbs, no new ones will be added over time.

In context, a preposition is always part of a phrase. A phrase is a group of words that is not a fully formed clause, as it doesn’t have both a subject and a verb. This means it can’t stand alone as a sentence.

Every phrase with a preposition in it is known as a prepositional phrase. These only need to contain a preposition and a noun/pronoun (which is then known as the object of the preposition).

For example:

in Paris

above the law

under pressure

When these prepositional phrases are included into sentences, the prepositions are used to link a noun to other words.

The dog was lost in Paris.

He felt above the law.

She thrives under pressure.

In these examples, the nouns (Paris, the law, pressure) are linked to other words (nouns, pronouns and verbs) through the underlined prepositions.

Depending on how the prepositional phrase is used, its function in the sentence differs.

If the prepositional phrase is describing a noun, it is playing the role of an adjective. However, if the phrase is describing a verb, adverb or an adjective, it is then acting as an adverb itself. Usually this is shown by which word the phrase follows.

This is clearer with some examples:

The lollypop on the floor is for Barry.

Here, the prepositional phrase on the floor is describing a noun, the lollypop. It is therefore acting as an adjective.

This can be demonstrated by replacing the phrase with an actual adjective:

The dirty lollypop is for Barry.

As you can see, dirty plays the same role as on the floor; it describes the lollypop.

The nun breakdanced across the room.

In this sentence, the prepositional phrase follows a verb, breakdanced. It is therefore acting as an adverb, as it describes how the nun breakdanced.

The nun breakdanced flamboyantly.

When replacing the phrase with an adverb, it is clear that the two acted in the same way.

Happy prepositioning!