Plural noun + noun

[gorikaz]

Dear professional teachers and native speakers,

I often get confused when I look at the noun like "Software Requirements Specification" or any other nouns which consist of "plural noun + noun."

Is this form grammatically correct?
Does not the plural part (= Requirements, in this case) have to be changed to a singular form (= Requirement) instead?

I learned that when a noun is used as a modifier, it must be in its singular form though...

Someone, please help me solve this problem.

[Mister Micawber]

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Although there are exceptions (e.g. ladies wear), the general rule is that the modifying noun-as-adjective is singular.

Still there are sometimes strong reasons for using the plural, and yours may be one of them. With 'software requirements specification', we clearly see that a number of requirements are to be specified, rather than just a single one.
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[gorikaz]

Mister Micawber,

Thank you for your clear comments on this issue.
I see, I have got your point.

So, in general, singular is used in most cases, but there are some exceptions, particularly when making the noun plural helps readers understand its context better, right?