Consider the following sentence as an example. I used some hair spray. What part of speech is hair? Intuitively, I want to say it's an adjective modifying spray since hair spray is two separate words and not a compound noun. Hair spray however, as paired nouns, is something that we've decided to call a thing suggesting it might be a noun or maybe some other part of speech as part of a noun cluster (if such a thing exists). A dictionary entry for hair does not describe hair as an adjective. I can think of several more examples like this:

money order, pocket comb, tip money.

Are money, pocket and tip adjectives or something else?

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    This is a hairy subject!
    – Hot Licks
    Commented Feb 3, 2019 at 16:31
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    Relevant:confusing examples of noun modifiers Commented Feb 3, 2019 at 16:37
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    Who says hair spray isn’t a compound noun? It absolutely is. Commented Feb 3, 2019 at 16:42
  • I see. I've never known open compound words were a thing. The reason I posed the question the way I did was to remove any potential political bias from someone's answer so I asked something analogous. My real query concerns the term the Democrat Party. (A pejorative created by Republicans originating in the '60s in the USA. The emphasis is placed on the rat syllable.) A critique is that it is grammatically incorrect and is properly the Democratic Party, democratic being the adjectival form of democrat and historically, the name of the party. Calling it a compound noun would make it acceptable. Commented Feb 3, 2019 at 17:25
  • It would have made for a much better question if you had asked that. It is absolutely a waste of time, yours and everyone else's, to ask a second question or to clarify in comments. Stick what you've got in mind in the question, be unbiased and clearly state you are looking at it from an English language point of view. There are enough users with common sense who won't get their knickers in a twist over the name of an American political party be it Democrat or Democratic. P.S the same could be said about the Republican Party, why isn't it called The Republic Party of the US?
    – Mari-Lou A
    Commented Feb 3, 2019 at 18:22

1 Answer 1


Compound nouns is when a noun forms a new noun when modified by either an adjective or, as in this case, by a noun. You can be more specific saying that it is a compositional compound noun, as opposed to a non-compositional noun phrase like red herring. You compose the meanings of hair and spray and can deduce the meaning of the resulting noun phrase hair spray. This is in contrast to red herring, which is neither red nor a herring.

It is also an spaced compound. The two nouns are written separate. It is a descriptive endocentric compound, since hair is modifying spray and the meaning ends up being a type of spray.


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