What Is A Compound Sentence?

A compound sentence is a complete sentence that contains two or more independent clauses joined by a conjunction, a semicolon, or a semicolon and a transitional word or phrase.

The English language has many types of sentences. Sentences can be simple, compound, or complex; you can even have a compound-complex sentence. It’s dizzying, so to keep everything clear, we will focus on the compound sentence.

What is a compound sentence

Dependent and Independent clauses

A dependent clause depends or counts on another part of the sentence to carry its weight. An independent clause can exist by itself as a sentence; it is a complete thought or complete sentence.

Simple And Compound Sentences

A simple sentence presents us with one independent clause.

Simple sentence explained

Melville sprinkles simple sentences among his many other sentences like seasoning in fine cooking. Here is one from Chapter 3 of Moby Dick:

Abominable are the tumblers into which he pours his poison.

Admittedly, it makes you curious: poison?

That is part of the value of a simple sentence. It has an impact. It is easily and quickly absorbed. It provides a rest area for your mind.

Within a sentence or two of that simple sentence, though, Melville writes:

He was trying his hand at a ship under full sail, but he didn’t make much headway, I thought.

This is a compound sentence. It combines independent clauses using the conjunction (connecting word) "but" :

  • He was trying his hand at a ship under full sail, (independent clause) but he didn’t make much headway, I thought. (independent clause).

Compound sentence structure example using But

Notice how the conjunction "but" stitches the clauses into a longer, more elegant sentence. Here is the same long, elegant sentence broken into its two independent clauses:

  • He was trying his hand at a ship under full sail. He didn’t make much headway, I thought.

Melville could have written the sentence that way. You can write compound sentences in three different ways, or break them apart into two simple sentences.

You can avoid compound sentences entirely by ending every thought with a period. Melville chose not to do that so he could continue his rhythm of short, medium, and long sentences.

Compound Sentences Conjunctions

Joining independent clauses requires either a semicolon, a semicolon and a transitional expression, or conjunctions, which are connecting words. Instead of ending an independent clause with punctuation (?, !, .) you end with a conjunction.

Here is a list of conjunctions you can use to create compound sentences:

  • For
  • And
  • Nor
  • But
  • Or
  • Yet
  • So

An easy mnemonic to remember these conjunctions is FANBOYS.

The easiest way to identify compound sentences in literature is to keep an eye out for a comma followed by one of the FANBOYS.

Compound Sentence Examples

Here are examples of compound sentences from Melville’s massive work. One compound sentence example for each conjunction:

  • For: I give the popular fishermen’s names for all these fish, for generally they are the best.
  • And: Ahab seemed a pyramid, and I, like a blazing fool, kept kicking at it.
  • Nor: There he sat; and all he could do—for all my polite arts and blandishments—he would not move a peg, nor say a single word, nor even look at me, nor notice my presence in the slightest way.
  • But: I turned round from eyeing the bed, but he had disappeared.
  • Or: “No,” said Peleg, “and he hasn’t been baptized right either, or it would have washed some of that devil’s blue off his face.”
  • Yet: To this, in substance, he replied, that though what I hinted was true enough, yet he had a particular affection for his own harpoon, because it was of assured stuff, well tried in many a mortal combat, and deeply intimate with the hearts of whales.
  • So: The horns of the cross-trees were sawed off on the other side, so that this old top-mast looked not a little like a gallows.

Compound Sentence With Semicolon

Compound sentences can also link together without one of the FANBOYS conjunctions. A semicolon can do all the heavy lifting, too. These are harder to spot because you are scanning for a puny piece of punctuation:

Compound sentence conjunctions

Melville makes glorious use of this method at the end of the first chapter of Moby Dick:

By reason of these things, then, the whaling voyage was welcome; the great flood-gates of the wonder-world swung open, and in the wild conceits that swayed me to my purpose, two and two there floated into my inmost soul, endless processions of the whale, and, mid most of them all, one grand hooded phantom, like a snow hill in the air.

A semicolon can carry the weight or use a semicolon, a transitional expression, and a comma.

Compound Sentences Structure

You have four choices when tangling with more than one independent clause:

  1. You can write the two or more independent clauses as separate sentences, using terminal punctuation (?,!,.)
  2. Join them using a FANBOYS word
  3. Connect them using only a semicolon
  4. Link them with a semicolon, transitional expression, and a comma

Compound sentence structure joining independent clauses

Writing is an art because you learn when to use each particular tool; no solution is “right” 100 percent of the time. We just used a semicolon to stitch together those two independent clauses, and we are guessing you did not even notice.

Usually, transitional expressions bog your fiction down but can set a proper pace for an academic paper. A semicolon can often carry the load, but you may want to avoid vastly different independent clauses joined solely with a semicolon:

  • The injured mineworker feebly limped home from the coal mine’s collapse; his hungry children cried for milk and bread.

In that case, a transitional expression is called for:

  • The injured mineworker feebly limped home from the coal mine’s collapse; consequently, his hungry children cried for milk and bread.

Compound Sentence Punctuation

Two problems with compound sentences are caused by attempts to be too clever or too brief:

  1. Fused or Run-On Sentences – Rather than use any punctuation or conjunction, you leave everything out and hope people will understand your two independent clauses (hint: they won’t)
  2. Comma Splices – Pity the poor comma, asked to perform the work of a semicolon by linking two or more independent clauses!

Examples of both make clear the role of the mighty semicolon, the coolness of the coordinating conjunction, or the transitional expression's ponderous power:

Fused sentence: The elephants eat acacia trees, or grasses, twigs, and bark they sleep briefly. They move many kilometers in the hot sun to watering holes they drink thirstily.

Comma splices: The elephants eat acacia trees, or grasses, twigs, and bark, they sleep briefly, they move many kilometers in the hot sun to watering holes, they drink thirstily.

With the correct structure and punctuation, we have this:

All fixed: The elephants eat acacia trees, or they eat grasses, twigs, and bark; they sleep briefly. They move many kilometers in the hot sun to watering holes; therefore, they drink thirstily.

A semicolon is used to join the first and second clause (both independent), and a semicolon followed by a transitional phrase and comma combine the last two independent clauses.

What you learned:

After working your way through this lesson and video, you have learned:

  • Compound sentence definition
  • Difference between a simple and a compound sentence
  • How to write a compound sentence using conjunctions
  • How to construct proper compound sentence structure using a semicolon
Instructor: Malcolm M.
Malcolm has a Master's Degree in education and holds four teaching certificates. He has been a public school teacher for 27 years, including 15 years as a mathematics teacher.

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