Perhaps our silliest memory trick yet.
“Is Comprised Of” and “Is Composed Of”
Now let’s talk about the phrases “is comprised of” and “is composed of.” One of these is allowed, and one is not. The one you can say is “is composed of,” so you could say, “Our nation is composed of many ethnic groups.” On the other hand, most grammar sources I checked (2, 3, 4) agree that “is comprised of” is an incorrect phrase. Just as you can’t say, “The house includes of seven rooms,” you can’t say, “The house is comprised of seven rooms” (5). You have to say, “The house comprises seven rooms.”
The American Heritage Guide to Contemporary Usage and Style (6), however, has noticed an interesting trend. In 1965, 54% of the usage panel disapproved of the phrase “is comprised of,” whereas in 2005, 65% approved, which I take to mean that only 35% disapproved. As with a number of constructions we’ve discussed here on the Grammar Girl podcast, they say “the traditional distinction may be destined to fall by the wayside.” This guide does suggest that you observe the traditional rule though.
How to Use “Comprise”
At the beginning of this show, we said that “comprise” means “contain,” but in her book Woe Is I the respected grammar writer Patricia O'Connor muddies the issue when she lists “to include” as a definition (7). This suggests that there could be more parts to the whole, contradicting the idea that when you use “comprise” you’re talking about all the parts.
If we use this definition, does it mean we could say, “The house comprises at least five rooms”? It would seem to make sense if we substitute the word “include” in this sentence. “The house includes at least five rooms.” Perhaps Fowler’s, another trusted resource, can help us. It states “the whole comprises all the parts.” The word “all” there seems pretty definitive.
On the other hand, the American Heritage Dictionary reveals that “comprise” means “to consist of,” to be composed of,” “to include,” and “to contain” (8). It goes on to clarify matters in its definition of “include”: “Comprise usually implies that all of the components are stated” (9). Notice that it said “usually.” It seems that to use “comprise” you must be talking about all the parts that make up something, but perhaps occasionally you can use it if more parts might be lurking somewhere.
Next: A Weird Memory Trick to Help You Remember the Difference