dictionary.cambridge gives 2 explanation of comprises

  1. to have things or people as parts or members; to consist of
  2. to be the parts or members of something; to make up something

Consider a set A = {B, C, D}, is it appropriate to say

"A comprises B, C and D"


"B comprises a fraction of A"?


1 Answer 1


You should take care with the word "comprise". It has several senses, but some senses are proscribed. That means that some people think that these meanings are bad English.

It is correctly used to say

The whole comprises the parts.

The list of parts should be a complete list of all the parts that make something.

A football team comprises ten outfield players and a goalkeeper.

There is a second usage, usually in the passive that is sometimes proscribed.

A football team is comprised of ten outfield players and a goalkeeper.

(Note that this idiom uses "of" and not "by")

You must allow that sometimes people will use "comprised of" in this way, but if you are writing yourself, you can be clearer by saying

A football team is composed of ten outfield players and a goalkeeper.

In your example it is certainly correct to say

A comprises B, C and D.

You will also hear:

A is comprised of B, C and D

But this meaning is rarely used in the active voice, so "B, C and D comprise A" would not be a common expression, and "B comprises a fraction of A" would similarly not be common.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .