Definition

A preposition is a word used to show the relation of a noun phrase to some other word.

For example

The ship was seen from the citadel.
He sailed upon the ocean in a ship of war.

The preposition always shows a relation between two terms,

• an antecedent
• a subsequent noun phrase

The subsequent noun phrase is called the object of the preposition. The preposition and the object united form a dependent element of the sentence. The preposition and its object combined form a prepositional phrase.

When the antecedent term is a noun, the phrase is an adjective prepositional phrase. When the antecedent term is a verb, a participle, an adjective, or an adverb, the phrase is an adverbial phrase.

For example

The rays of the sun; that is, the solar rays.
The phrase of the sun modifies the noun rays and is an adjective prepositional phrase.
The case was conducted with skill; that is, skillfully.
The phrase with skill modifies the verb phase was conducted and is an adverbial prepositional phrase.

The object of the preposition is not always a single word. The object may be a single word, a phrase, or a clause.

For example

The city was about to capitulate when Napoleon arrived.

The preposition is sometimes placed after its object.

For example

While its song, sublime as thunder, rolls the woods along.

The preposition and the object sometimes precede the word on which they depend.

For example

Of all patriots, Washington was the noblest.

List of Prepositions

The following words are the most important prepositions in English.

• aboard
• before
• excepting
• until
• about
• behind
• for
• through
• above
• below
• from
• to
• across
• beneath
• in
• of
• after
• beside
• into
• on
• toward
• against
• notwithstanding
• over
• under
• along
• besides
• unto
• underneath
• amid
• between
• up
• amidst
• beyond
• betwixt
• upon
• among
• by
• past
• with
• amongst
• concerning
• regarding
• within
• around
• down
• respecting
• without
• throughout
• during
• round

A complex preposition consists of two words parsed as a single word.

For example

according to
as to
as far
out of
instead of
because of
off from
over against
round about
from among
from between
from around
from before

The first word of the phrase is sometimes parsed as an adverb.

In some combinations as the following, the preposition may be parsed as an adverb when it is not followed by an object.

• put in
• go up
• go down
• cut through
• pass by
• climb up

For example

The captain stood in for the shore.
They rode by in haste.

Some words commonly employed as prepositions are occasionally used as adverbs.

For example

before
after
until
above
beneath
for
on
in

Some words commonly employed as adverbs or as conjunctions are sometimes used as prepositions.

For example

but
save
despite

Off is usually an adverb but may be parsed as a preposition when followed by an object.
Instead is either a preposition or equivalent to a preposition and a noun.