What are conjunctions?
What are conjunctions? Conjunctions join words or groups of words together. The most common ones are and, or, and but.

There is no simple rule about whether you should use a comma before a conjunction. The rules on that are quite complicated (covered below).

You can start a sentence with a conjunction, but you shouldn't do it too often.

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What Are Conjunctions?

Conjunctions are used to join words or groups of words together. The most common ones are and, or and but. (There are others – see Conjunctions in the Glossary of Terms.)

Conjunctions can be categorized into one of three groupings:

Coordinating Conjunctions

Coordinating conjunctions are the ones which tend to spring to mind when people think about conjunctions. They include and, but, or, nor, for, so and yet. They are used to join individual words, phrases and independent clauses.

Coordinating Conjunctions Joining Individual Words:

  • Jamie, Adam and Lee arranged to meet by The Bull at 7 o'clock.
  • (conjunction and groups Jamie, Adam + Lee)
  • It is a small but practical kitchen.
  • (conjunction but groups small + practical)
Coordinating Conjunctions Joining Individual Phrases:

  • The finance manager or his new deputy will notify you when the report is ready.
  • (conjunction or groups manager + deputy)
  • John or his new deputy from Holland will notify you when the report is ready.
  • (You can join a mix of words and phrases with a coordinating conjunction. Here, the conjunction or groups the word John + the phrase his new deputy from Holland.)
Coordinating Conjunctions Joining Individual Clauses:

  • A little sincerity is a dangerous thing, and a great deal of it is absolutely fatal. (Oscar Wilde)
  • (conjunction and joins two independent clauses)

  • We are all in the gutter, but some of us are looking at the stars. (Oscar Wilde)
  • (conjunction but joins two independent clauses)
  • History will be kind to me, for I intend to write it. (Winston Churchill)
  • (conjunction for joins two independent clauses)
Coordinating means of equal rank. Usually, the elements joined by a coordinating conjunction are of equal rank. Therefore:

  • Words, phrases, non-independent clauses can be grouped together.
  • Independent clauses can be grouped together.
It is unusual to see a mix of these groups joined by a coordinating conjunction.

Correlative Conjunctions

Correlative conjunctions appear in pairs. For example, either...or, neither...nor, whether...or and not only...but also

  • This man is either dead or my watch has stopped. (Groucho Marx)

Subordinating Conjunctions

Subordinating conjunctions include: after, although, as, because, before, if, once, since, than, that, though, till, until, when, where, whether and while.

They are used to show the relationship between the independent clause and the dependent clause.

  • Keep your hand on the wound until the nurse asks you to take it off.
  • Personally I'm always ready to learn, although I do not always like being taught. Sir Winston Churchill (1874-1965)
  • We can't all be heroes because somebody has to sit on the curb and clap as they go by. Will Rogers (1879-1935)
Click on the coordinating conjunctions:


Errors with Conjunctions

Conjunctions do not normally cause serious errors, but writers are sometimes confused about when to place a comma before a conjunction. Unfortunately, there is no simple rule, such as: Never put a comma before and.

The guidelines are explained in the lesson Conjunctions and Commas.

Comma before And in a List?

Most lists look like this:

  • Thing, another thing, another thing, and the final thing.

The conjunction sits before the final thing. In this case, it's the word and. The big question is whether the comma before the and is right or wrong.

When there are just two list items, there is no need for a comma before the conjunction. For example:

  • Thing and the final thing.
  • (No comma is required because it is a list containing just two list items.)
Here's real example:

  • I know George and Toby.
  • (No comma required before the and.)
The whole world is agreed on not needing a comma with just two list items.

However, when there are more than two list items, the world is divided on whether there should be a comma. There is no right answer. You have to pick a convention and stick with it.

The comma before the conjunction is called an Oxford Comma. Some people consider the Oxford Comma to be a waste of ink, while others strongly campaign for its inclusion. In general terms, the Oxford Comma is more common in the US than it is in the UK (despite it being called the Oxford Comma).

Followers of the Oxford Comma
(generally Americans)
Avoiders of the Oxford Comma
(generally Brits)
  • I went to the shop for eggs and butter.
  • (There is no need for a comma with just two list items.)
  • She went to the shop for eggs, milk, and butter.
  • She went to the shop for eggs, milk and butter.
  • Carl, David, and Sarah were all there.
  • Carl, David and Sarah were all there.
  • I went to the shop for eggs and butter.
  • (There is no need for a comma with just two list items.)
  • She went to the shop for eggs, milk, and butter.
  • She went to the shop for eggs, milk and butter.
  • Carl, David, and Sarah were all there.
  • Carl, David and Sarah were all there.

There is another quirk. On occasion, it may be appropriate to use a comma with the conjunction in a simple list (even a list with just two list items). This could be for the sake of tidiness or to eliminate ambiguity. (This topic is also covered in the lesson Commas in Lists.) 


  • The news will be shown after Dangermouse, and Rug Rats.
  • (Without the comma, people could think that Dangermouse and Rug Rats is one programme.)

  • The train will stop at Watford, Harrow, Pinner, Watford, and Bushey.
  • (Watford and Bushey could be one place, like Bath and Wells.)

  • The emblem is an amalgamation of the British and Irish flags, the Stars and Stripes, and the Hammer and Sickle.
  • (The word and appears lots of times in this example. The comma before
    the and makes it easier for the reader to identify the last list item.)

In the past, schools were rigid in their ruling that sentences could not start with conjunctions, such as And or But. However, nowadays, this practice is considered acceptable.

  • I was certain Petrovski did it for financial gain. But, having read his diary, I have a new theory.
  • I've had a perfectly wonderful evening. But, this wasn't it. (Groucho Marx)

The two most common conjunctions used in this way are And (meaning In addition) and But (meaning However). It is usual to follow each with a comma.

Whilst it is acceptable to use And or But to start a sentence, this practice should be limited and only used for impact or to control the flow of text. If you find yourself using them too often, you should consider changing the style of your writing. Starting your sentences with conjunctions will annoy your readers if you do it too often.

See also:

What are adjectives?
What are adverbs?
What are interjections?
What are nouns?
What are prepositions?
What are pronouns?
What are verbs?
Conjunctions and commas
Conjunctions and semicolons
Commas before conjunctions (and, or, but)
More than I or more than me?
List of easily confused words

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