Writers often confuse words with closely related meanings and similar spellings. Comprise and compose are among them.
Comprise is a verb that means “includes” or “consists of.” For example, Canada comprises 10 provinces.
Compose also is a verb and means “to make up the parts of.” To wit, Ten provinces compose Canada.
You’ll notice that in both of the given examples, the sentences are in active voice. You can create a passive voice structure for compose through is composed of as in Canada is composed of 10 provinces. The active voice version of the verb, however, makes for tighter writing.
And while some writers use is comprised of (Canada is comprised of 10 provinces) , it’s generally frowned upon. The Chicago Manual of Style calls it poor usage while The AP Stylebook forbids the structure.
A way to remember the difference between the words is comprise follows the structure of “whole to parts” while compose is “parts to whole.”
My name is Rob Bignell. I’m an affordable, professional editor who runs Inventing Reality Editing Service, which meets the manuscript needs of writers both new and published. I also offer a variety of self-publishing services. During the past decade, I’ve helped more than 300 novelists and nonfiction authors obtain their publishing dreams at reasonable prices. I’m also the author of the 7 Minutes a Day… writing guidebooks, four nonfiction hiking guidebook series, and the literary novel Windmill. Several of my short stories in the literary and science fiction genres also have been published.