Comprise vs. Compose: What’s the Difference?

The words comprise and compose are two words that are increasingly misused in popular writing, so you should be sure to use them with care and precision. Their meanings are closely related, so the confusion between them is understandable. After all, just a few letters separates them from one another.

But, in order to keep ourselves from falling into sloppy writing, we should know how to tell these two words apart.

What is the Difference Between Comprise and Compose?

In this post, I want to discuss the definitions of these two words, their functions within a sentence, and give you a few tricks to remember their differences. After reading this post, you shouldn’t have to question yourself ever again as to whether or not you’ve made the correct word choice.

When to Use Comprise

define comprisingComprise is a transitive verb and means to be made up of, to consist of, and to include. Since comprise is a transitive verb, expect to see a direct object somewhere nearby in the mix of things. For example,

  • The United States comprises 50 states.
  • A full deck comprises 52 cards.

A good way to think about comprise is that the whole comprises the parts. Something that is complete comprises many parts. Let’s take another example,

  • A pizza comprises eight slices.

As we see, the full and complete pizza comprises eight smaller parts, which are slices.

The AP Stylebook states that comprise is best used with the active voice and followed by a direct object. It suggests avoiding a passive use of comprise.

When to Use Compose

define-composingCompose is also a transitive verb, but it has a slightly different meaning. Compose is to make up the constituent parts of, to form the substance of something. As is the case with comprise, you should expect an object to follow. For example,

  • Fifty states compose the United States.
  • Fifty-two cards compose a full deck.

As you can see, in these sentences the parts, rather than the whole, are the subjects. With compose, the parts compose the whole. Let’s look at our pizza example again,

  • Eight slices compose a pizza.

In this sentence we are saying that eight slices make up a pizza. In the previous example, we were saying that a pizza is made up of eight slices. The difference is subtle yet important.

Unlike comprise, compose can be used both actively and passively in a sentence. For example,

  • Eight main islands compose Hawaii. (Active)
  • Hawaii is composed of eight main islands. (Passive)

Is Comprised Of, Is Composed of

What about the phrases “is comprised of” and “is composed of?” One of these you can use and one of these you can’t use.

Both of these phrases are examples of the passive voice, and as we discusses earlier, you cannot use the passive voice when using the word comprise, but you can use the passive voice when using compose. For example,

  • The book is comprised of 12 chapters. (WRONG)
  • The book comprises 12 chapters. (CORRECT)
  • Twelve chapters compose the book. (CORRECT)
  • The book is composed of 12 chapters. (CORRECT)

The Chicago Manual of Style, while recognizing its increasing popularity, states that the phrase “is comprised of” is poor usage and should be avoided. On the other hand, “is composed of” is perfectly acceptable.

Summary

These two words, compose vs. comprise, have very subtle differences, so you should use them with care.

The whole comprises the parts.

The parts compose the whole.

You can use the phrase “is composed of,” but you cannot use the phrase “is comprised of.”

Quiz and Sentence Examples

Test your knowledge with the following sentences,

  1. Many ethnic groups ______ the United States.
  2. My wardrobe ______ these outfits.
  3. These outfits ______ my wardrobe.
  4. The melody is ______ of these notes.

Answers

  1. Compose
  2. Comprises
  3. Compose
  4. Composed

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