grammaticality - Thing count or thingS count

When there are many of things what of the following will be correct:

• thing count, thing collection, ... (singular thing)


• things count, things collection, ... (plural things) ?

Answer

You would use the singular form before collection because you are describing the singular type of the collection, like an adjective. After, you would use plural, because you are describing what comprises the collection. For example:

A doll collection

A stamp collection

versus

A collection of dolls

A collection of stamps