Comprise or Compose?

by Craig Shrives

Comprise or Compose?

What is the difference between "comprise" and "compose"?
  • "To comprise" means "to consist of."
    • The cake comprises four slices.
      • (Notice that the word "of" is not used with "comprise.")
  • "To compose" means "to make up."
    • Four slices compose the cake.

Comprised or Comprised Of?

Here are three common issues related to "comprise":
  • (1) Do not use "of" with "comprise."
    • The play comprises of three parts.
    • The play comprises three parts.
  • (2) Avoid the construction "is comprised of."
    • The play is comprised of three parts.
      • (Many consider this to be non-standard English. To play it really safe, avoid "comprised of." However, if it works well in your sentence and rewording is awkward, go for it.)
  • Avoid naming the constituent parts first.
    • Three parts comprise the play.
comprise, comprise of, compose, or composed of
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More about "Comprise" and "Compose"

There is often confusion over "comprise" and "compose." The situation is not helped by ongoing debate about how to use "comprise." If you stick to the guidelines below, you will be on safe ground.

Comprise

"To comprise" means "to consist of" or "to be made up of." It is used to state that something "is made up of" smaller parts. Do not use the word "of" with comprise.

Examples:
  • The water molecule comprises two atoms of hydrogen and one atom of
    oxygen.
    • (The whole comprises the smaller parts.)
  • The water molecule comprises of two atoms of hydrogen and one atom of
    oxygen.
    • (Do not use the word "of" with "comprise.")
  • Two atoms of hydrogen and one atom of oxygen comprise the water molecule.
    • (This is one of the areas under debate. Many advocate that "comprise" cannot be used to say the smaller parts make up the whole. They believe this is when "compose" should be used. If you adhere to this ruling too, you will be on safe ground.)
  • The three wise monkeys comprise Mizaru (see no evil), Kikazaru (hear no evil), and Iwazaru (speak no evil).
  • The quadriceps femoris comprise the rectus femoris, the vastus medialis, the vastus intermedius, and the vastus lateralis.

Is Comprised Of

The construction "is comprised of" (it correctly includes the word "of") is considered by many to be non-standard English. To avert criticism, reword your sentence to avoid this construction.

Examples:
  • The water molecule is comprised of two atoms of hydrogen and one atom of oxygen.
    • (Marking this wrong is harsh, but some of your readers may frown at this version.)
  • The water molecule comprises two atoms of hydrogen and one atom of oxygen.
    • (This is the non-contentious version.)

Compose

"To compose" means "to make up" or "to make." It is used to state that smaller parts make up the whole (i.e., the opposite of comprise). Do not use the word "of" with compose.

Examples:
  • Mercury, Venus, Earth, and Mars compose the inner planets.
  • The rectus femoris, the vastus medialis, the vastus intermedius, and the vastus lateralis compose the quadriceps femoris.
  • Two atoms of hydrogen and one atom of oxygen compose the water molecule.

Is Composed Of

The construction "is composed of" (it correctly includes the word "of") does not attract the same criticism as "is comprised of."

Examples:
  • USA is composed of 50 states.
  • The water molecule is composed of two atoms of hydrogen and one atom of oxygen.

Name All the Constituent Parts

Make sure you name all the constituent parts when using "comprise" or "compose."
  • Since August 2006 when the International Astronomical Union declassified Pluto as a planet, only eight planets compose our solar system.
    • (Our solar system also includes the Sun, an asteroid belt, and a number of dwarf planets. Therefore, "compose" is incorrect in this example.)

Beware "Include"

Do not name all the constituent parts when using "include."
  • The water molecule includes two atoms of hydrogen and one atom of oxygen.
  • The water molecule includes one atom of oxygen.
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See Also

adverse or averse? affect or effect? appraise or apprise? avenge or revenge? bare or bear? complement or compliment? dependant or dependent? discreet or discrete? disinterested or uninterested? e.g. or i.e.? envy or jealousy? imply or infer? its or it's? material or materiel? poisonous or venomous? practice or practise? principal or principle? cannot or can not? who's or whose? Common errors and FAQs List of easily confused words