What is a Coordinate Clause?

There is plenty of confusion over what constitutes a coordinate clause. Let’s list few prevailing understandings with this example sentence: Tom hit the ball hard, but he couldn’t clear the fence.

1. The above sentence contains two coordinate clauses: Tom hit the ball hard and He couldn’t clear the fence.

2. The above sentence contains one coordinate clause: He couldn’t clear the fence.

3. The above sentence contains one coordinate clause: But he couldn’t clear the fence. Note that the clause is inclusive of but.

I went through couple of reliable sources – grammar books, dictionaries, and glossaries – to find out their take on the topic. Almost all support first of the above three understandings, but there is more to coordinate clauses.

What’s a coordinate clause?

Let’s start with what these four sources say on coordinate clause.

1. Oxford Learner’s Dictionary

According to Oxford Learner’s Dictionary, a coordinate clause is ‘each of two or more parts of a sentence, often joined by and, or, but, etc., that make separate statements that each have an equal importance’.

Now, parts is bit vague, but the dictionary clarifies through an example. It says that the sentence It stopped raining and the sun came out contains following two coordinate clauses: It stopped raining and the sun came out.

2. Merriam-Webster Dictionary

According to Merriam-Webster Dictionary, a coordinate clause is ‘one of two or more clauses in a sentence that are of equal importance and usually joined by and, or, or but’. That’s similar to, but more precise than (part vs. clause), what Oxford Learner’s Dictionary says. It doesn’t provide any example though.

3. Glossary of Linguistic Terms by SIL

According to Glossary of Linguistic Terms by SIL, ‘a coordinate clause is a clause belonging to a series of two or more clauses which

• are not syntactically dependent on one another
• are joined by means of a coordinating conjunction, a connective, and parataxis’

It cites few examples (the underlined parts are coordinate clauses):

4. The Cambridge Grammar of the English Language by Rodney Huddleston and Geoffrey K. Pullum

The book doesn’t provide a definition of coordinate clause, but it mentions that ‘in a compound sentence the immediate constituents are two or more COORDINATE clauses’. The book then mentions that the sentence Ann applied for a grant and they gave her $50,000 has two coordinate clauses. This is essentially in line with the other three.

What do we infer from above definitions of coordinate clause?

We can draw two inferences:

1. A solitary independent clause can’t be a coordinate clause. If you notice, all three definitions say ‘two or more’. And this goes not just with the dictionary meaning of word coordinate (coordination requires more than one thing) but also with the similar concept of coordinate adjective, wherein adjectives are called coordinate only if two or more adjectives of equal weight modify the same noun.

This negates the second and third understandings about coordinate clauses we saw at the beginning of the post, which say that only second of the two independent clauses is a coordinate clause. (Writing in English by Dr George Stern supports the third understanding of coordinate clause, but it’s a significant minority position. Note that it’s not uncommon for grammar books to differ on terminologies and definitions.)

2. Coordinate clauses are two or more independent clauses in a sentence. If you know what simple, compound, complex, and compound-complex sentences are, you would understand that coordinate clauses can occur in only compound and compound-complex sentences.

But the definition of coordinate clause doesn’t preclude dependent clause

Of the three definitions, two mention coordinate clause as clause, even though all examples they cite contain only independent clauses. (The third definition too most likely means clause when it says part.) But a clause can also be a dependent clause.

As long as a dependent clause fulfils the condition of being a coordinate clause, which is presence of two or more clauses of equal weight, it is a coordinate clause. A Comprehensive Grammar of the English Language by Randolph Quirk et al. mentions an example of dependent clauses as coordinate clauses.

I have heard that you are a car mechanic and that your brother is a plumber.

The two dependent clauses are equal in weight as they’re joined by and.

Having said that, most references to coordinate clauses in books and other text are of independent clauses, like we saw in most examples cited so far. And rarely of dependent clauses. That’s why, in common parlance, coordinate clauses are associated with independent clauses.

If the new clause terminology – coordinate clause – confused you, then remember that it’s not a new type of clause. The fundamental clauses remain dependent (or subordinate) and independent (or main or principal). Coordinate clause is just a way of grouping certain type of dependent and independent clauses (those with equal weight). Its true counterpart is embedded clause, like independent clause’s is dependent clause.

What’s the difference between coordinate clause and independent clause?

Seeing examples of coordinate clauses in only compound sentences, many treat coordinate clause and independent clause as one and same. But that’s not true.

As we saw earlier, a dependent clause too can be a coordinate clause. Second, a clause can be coordinate only if it is in company of one or more clauses.

Let’s take few examples to make this distinction clear.

1. The researcher claims to have discovered a new species of frog.

Independent clause: One

Dependent clause: Zero

Coordinate clause: Zero

Since the sentence contains just one clause, the question of coordinate clause doesn’t even arise.

2. The researcher claims to have discovered a new species of frog, though others are sceptical about the claim.

Independent clause: One

Dependent clause: One

Coordinate clause: Zero

The sentence doesn’t contain two or more clauses of equal weight. Note that a dependent and an independent clause can never be of equal weight.

3. The researcher claims to have discovered a new species of frog, but the discovery needs to be peer-reviewed.

Independent clause: Two

Dependent clause: Zero

Coordinate clause: Two

Here, the independent clauses and the coordinate clauses are one and same.

4. The researcher’s claim, which is yet to be published and which is yet to be peer-reviewed, has been met with scepticism.

Independent clause: One

Dependent clause: Two

Coordinate clause: Two

Here, the dependent clauses and the coordinate clauses (underlined) are one and same.

5. The researcher claims to have discovered a new species of frog, though others are sceptical about the claim as his similar claims in the past were found to be false.

Independent clause: One

Dependent clause: Two

Coordinate clause: Zero

The two dependent clauses aren’t of equal weight or importance. Note that they’re not connected with a coordinating conjunction like the dependent clauses in the previous example are.

What’s a coordinate sentence?

A Glossary of English Grammar, Geoffrey Leech, cites this example of coordinate sentence: He scored a goal, and everybody cheered.

From this example, can you guess what’s a coordinate sentence? A coordinate sentence is a sentence that contains two or more independent clauses joined by coordinating conjunctions. In other words, a coordinate sentence is nothing but a compound sentence.