Compose vs. Comprise?

Here’s just one more example of two words that are often used interchangeably – and incorrectly. I can’t tell you how many times I’ve seen something like:

Our IT department is comprised of five full-time experts
The book is comprised of three sections

It’s a widespread assumption that “compose” and “comprise” basically mean the same thing. But that’s not quite true:

Compose means “to put together” or “to create.” For example, you’d compose a symphony, or you’d compose a letter to your aunt. This word is often used in the passive voice – no doubt, you’ve seen something like this:

The exhibit is composed of several works of art
The United States is composed of 50 states.
The group is composed of several experts.

Comprise, on the other hand, means “to include” or “to embrace.” So, you might say, for example:

The exhibit comprises several works of art.
The United States <comprises 50 states.
The group comprises several experts.

And, here’s another tip that might make it easier to remember which word to use: The AP Stylebook Online cautions that “comprise” shouldn’t be used in the passive voice, so “comprised of” is never a good option.

Got any more confusing word choice questions? Have a question about an obscure grammar rule? We’d love to hear from you.