This one frustrates me, because it’s so often used incorrectly. Comprise means to contain or consist of. A whole comprises its parts; the U.S.A comprises 50 states. In effect, comprise is a synonym of “is composed of.” A thing is not “comprised of” its parts.
Correct: “The proposal comprises three sections.” Correct: “The proposal is composed of three sections.” Bloody Wrong: “The proposal is comprised of three sections.”
Again, the whole comprises the parts. Parts compose a whole. Comprise = Is composed of.
Now, if you look in some dictionaries, you will see “comprised of” listed as an idiom. Idioms are considered dialects, and often spring from incorrect usage. In effect, it’s something people say wrong for so long, others know what it means. However, in formal writing, “comprised of” is still wrong, and people will snicker at you behind your back.
You don’t want that, do you?