Comprise or Compose?

What Is the Difference between "Comprise" and "Compose"?

"Comprise" and "compose" are easily confused because they both relate to the makeup of something.
  • "Comprise" means "to consist of."
    • The cake comprises four slices. correct tick
    • (Notice that the word "of" is not used with "comprise.")
  • "Compose" means "to make up."
    • Four slices compose the cake. correct tick

"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. wrong cross
    • The play comprises three parts. correct tick
  • (2) Avoid the construction "is comprised of."
    • The play is comprised of three parts. wrong cross
    • (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.)
  • (3) Avoid naming the constituent parts first.
    • Three parts comprise the play. correct tick
comprise, comprise of, compose, or composed of

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.

Example sentences with "comprise":
  • The water molecule comprises two atoms of hydrogen and one atom of oxygen. correct tick
  • (The whole comprises the smaller parts.)
  • The water molecule comprises of two atoms of hydrogen and one atom of oxygen. wrong cross
  • (Do not use the word "of" with "comprise.")
  • Two atoms of hydrogen and one atom of oxygen comprise the water molecule. wrong cross
  • (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). correct tick
  • The quadriceps femoris comprise the rectus femoris, the vastus medialis, the vastus intermedius, and the vastus lateralis. correct tick

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. wrong cross
  • (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. correct tick
  • (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.

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

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. correct tick
  • The water molecule is composed of two atoms of hydrogen and one atom of oxygen. correct tick

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. wrong cross
  • (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. wrong cross
  • The water molecule includes one atom of oxygen. correct tick
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This page was written by Craig Shrives.