I feel like there is no difference between the two words. Would you tell me what is the difference between them?

I'm an electrical engineer. Which one should I use to speak about electricity, electrons, wires, electromagnetic waves and so on...?

Thank you,

1 Answer 1


There's no difference in meaning between 'consist of' and 'be composed of'. Both are used to describe what something is formed or made of.

The difference is between their usage. The former is used in the active voice, whereas the latter is in the passive voice.

Besides, the use of the latter is more formal. The former can be used both in spoken and written formal English.

  • 7
    I completely agree that they're interchangeable. I just wanted to add a side note about how I personally choose which to use. Since compose is a also a verb meaning "to build" or "to create", I think that sometimes "composed of" is used a little more often when identifying the elements of something that's been constructed (The building is composed of bricks), while "consists of" would be used for something natural or abstract (The group of friends consists of four boys and two girls). Again, maybe just a personal preference and definitely still interchangeable at the end of the day. Commented Feb 25, 2016 at 15:48
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    When I read "composed of" I infer that there's a "composition", and "consist of" gives me "consistence" in the same fashion. But that's a nuance remark.
    – talles
    Commented Feb 25, 2016 at 16:00
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    Dr DrfbagIII, I appreciate your comments, but there are many sentences in dictionaries using be composed of and consist of without making a distinction between these phrases.
    – Khan
    Commented Feb 25, 2016 at 16:31
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    What @Dr DrfbagIII said. Personally, in contexts where I feel the constituent parts have to be "gathered together" to form something, I'm probably more likely to go for comprising. Dunno if that naturally follows somehow from the fact that etymologically, comprise started life with the now-obsolete sense To lay hold on, take, catch, seize. Commented Feb 25, 2016 at 17:26
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    @Dr.D - I agree with your usage note, too. And if neither one sounds right, I might use made from, as in: This cake batter is made from flour, milk, sugar, and eggs. (Somehow, neither composed of nor comprised from seems like the right word there. It's tough to explain.)
    – J.R.
    Commented Feb 25, 2016 at 22:52

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