General Writing and Grammar Help/Compound Nouns


Dear Ted,

I hope that all has been well with you.   

I am trying to understand the use of the terms “air conditioning” and “air conditioner”.

I hope you will not mind helping me with the following questions:

Can you please tell me if “air conditioning” and “air conditioner” are both classified as compound nouns.

Can you also please help me with the use of the term “air conditioning”    For example,   why does it sound correct to say -  “My car has air conditioning”  and “The air conditioning in my car is broken”  but it sounds incorrect to say -“My car has an air conditioning”

Thank you.

Very Sincerely,


Dear Rich:

**** I thought of something else to add to the oddity of the language.  "Courthouse" is
a compound noun, but it can also be an adjective:  A party was held for the courthouse
staff. The courthouse offices are on the first level of the building; the courtrooms are
on the second level.  



Thank you for sending your question through Allexperts.  When I tried to read this
question through my regular e-mail account, the letters were gigantic.  They were billboard
size.  In all my years, this problem has occurred just once before.  The message come from
a student in Pisa, Italy.  We discovered that there was something wrong with his e-mail,
because he sent the message again, using a different e-mail account, and there were no

I will never understand computers or the internet.

Now, to your question --


Check out this handy guide:

Because our language customs change often, heed the advice at the very end of the screen.
Check your dictionary.

"Air-condition" is correct.  So is "air-conditioning."  However, the device itself is NOT
hyphenated; it is "air conditioner."

ALL three are compound nouns.

*** "My car has an air conditioning" is incorrect, because the name of the device is "air conditioner."  Similarly, you would not say "an refrigerator."  

*** I believe that I gave you an example of how compound words are formed:

First, there was "court house."  The noun was "house," and "court" was the adjective.

Then, "common usage" changed and the two words became a hyphenated phrase "court-house."

Finally, common usage felt that the hyphen was unnecessary and the phrase was changed
to the compound noun "courthouse."

A person who patrols a beach and looks out for the safety of others "guards" the people.
He is supposed to save lives.  Thus, a new compound noun was coined:  lifeguard.

To get back to your question -- You cannot say "an air-conditioning."  You CAN use
"air-conditioning" as an adjective:  "My car has an air-conditioning system."


I hope so.


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Ted Nesbitt


I am the bibliographic instruction and reference librarian at a public college. Some members of the English department recommend me to their students. I offer assistance in grammar, punctuation, sentence structure, and paragraph development. My master`s thesis concerns William Faulkner`s tragic novels. I formerly taught advanced placement English at two schools in the Philadelphia area.


I have been one of the highest-ranked volunteers in this category for more than a decade.

B. A. and M. A in English; MSIS in Library & Information Sciences; graduate study in philosophy

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