Resources · Education · Grammar
What Is a Compound Sentence?
In English grammar, a compound sentence is a sentence that connects two or more independent clauses with a coordinating conjunction or a semicolon. An independent clause is a group of words containing a subject and a verb that can stand alone as a complete sentence. Compound sentences allow writers to connect related ideas, build rhythm, and construct sophisticated texts.
6 min read
The Anatomy of a Compound Sentence
To understand compound sentences, you must understand the difference between independent and dependent clauses:
- Independent Clause: Contains a subject and a verb and expresses a complete thought. Example: "The storm raged."
- Dependent Clause: Contains a subject and a verb but starts with a subordinating conjunction, leaving the thought incomplete. Example: "Because the storm raged."
A compound sentence contains two or more independent clauses and no dependent clauses.
Methods for Joining Clauses
There are three primary ways to join independent clauses in a compound sentence:
1. Comma + Coordinating Conjunction (FANBOYS)
You can place a comma and one of the seven coordinating conjunctions between the clauses:
- For: Explains reason (similar to because).
- And: Adds information.
- Nor: Joins negative statements.
- But: Shows contrast.
- Or: Presents alternatives.
- Yet: Shows concession or contrast.
- So: Indicates result or consequence.
Example: "I wanted to go for a run, but it started to rain."
2. Semicolon
If the two clauses are closely related, you can join them with a semicolon alone (no conjunction is needed):
Example: "The sky grew dark; the wind began to howl."
3. Semicolon + Conjunctive Adverb + Comma
You can use a semicolon and transition words (like however, therefore, moreover, or otherwise) followed by a comma:
Example: "She studied diligently for months; therefore, she passed the exam with ease."
Sentence Structure Comparisons
Understanding how compound sentences compare to other sentence types helps avoid run-on sentences and fragments:
| Sentence Type | Clause Composition | Example |
|---|---|---|
| Simple | 1 Independent Clause | "The train arrived late." |
| Compound | 2+ Independent Clauses | "The train arrived late, so we missed our meeting." |
| Complex | 1 Independent + 1+ Dependent | "Although the train arrived late, we made it in time." |
| Compound-Complex | 2+ Independent + 1+ Dependent | "Because the train was late, we missed our meeting, and we had to reschedule." |
Linguistic Analysis Tools
Analyze sentence variety, count words, and calculate text statistics:
Frequently asked questions
The seven coordinating conjunctions used to connect independent clauses in a compound sentence are: For, And, Nor, But, Or, Yet, and So. An easy way to remember them is the acronym FANBOYS.
A comma splice occurs when you join two independent clauses with only a comma, without a coordinating conjunction (e.g., 'I went to the store, I bought milk.'). To fix it, you must add a conjunction after the comma, change the comma to a semicolon, or split the clauses into two separate sentences.
Yes. While most compound sentences consist of two independent clauses, it is grammatically correct to join three or more. For example: 'The sun rose, the birds sang, and the forest came alive.' Each clause has its own subject and verb and could stand alone as a sentence.
No. A sentence with a single subject and a compound verb (e.g., 'She ran to the store and bought milk.') is a simple sentence, not a compound sentence, because it contains only one clause. A compound sentence must contain at least two separate independent clauses, each with its own subject and verb.