Is the superclub a noun or an adjective in this sentence?

[usignolo]

Here is the sentence:

Before the superclub boom that happened either side of the millennium, DJs started out as relatively anonymous record changers, with a handful known only to committed dance acolytes.

I would like to know if the superclub here is a noun or an adjective.

P.S. My friend told me that the noun didn`t use plurally when it is used as an attribute, he gave an example "computer magazine". So he thinks that superclub is a noun in this sentence. But I think that this is an adjective. Who of us is right?

If my friend is right, could you advise me a book where I can read the rule he told me?

Thanks in advance,
Max.

[Soup]

Hello usignolo

It's a compound noun in form that functions as an adjective. It modifies the noun boom.

Before the superclub boom that happened either side of the millennium, DJs started out as relatively anonymous record changers, with a handful known only to committed dance acolytes.

Test it:

[1] You know it's an adjective if you delete it and resulting sentence remains grammatical:

• Before the superclub boom ...
• Before the boom ... <deleted superclub>

[2] You know it's an adjective if it answers the question What kind of?:

• What kind of boom? A superclub one.

[3] You know it's a noun if it functions as the subject or object of the verb:

• Before the superclub that happened ...

[Abstract Idea]

Thank you very much for such a wonderful wise lesson Soup !

[usignolo]

Dear Soup,
Thanks a lot. Your explanation is perfect!
As I understood, I should translate this word into Russian as an adjective. Am I right?

[Soup]

Dear Soup,
Thanks a lot. Your explanation is perfect!
As I understood, I should translate this word into Russian as an adjective. Am I right?

Yes. It describes the noun boom (a rapid increase in price, development, numbers, etc.: a boom in housing construction.) In other words, what kind of boom/increase was it? It was an increase in superclubs (n.); therefore, a superclub (adj.) boom; Cf. an increase in bike sales (n.), a bike-sale (adj.) boom.

[usignolo]

Many thanks!
Now everything is clear!