Fabric / Fabrics

[Tedwonny]

I have read
fabric noun (CLOTH) - definition in the British English Dictionary & Thesaurus - Cambridge Dictionaries Online
and
fabric - Definition from Longman English Dictionary Online

and it is extremely vague what the difference between fabric and fabricS is. Dictionaries often simply label them as C / U without further elaboration of the usage between the semantic differences between its countable and uncountable forms. I was thinking:
fabric = a material - a concept and hence uncountable and shouldn't be pluralized
fabrics = different types of fabrics? stressing the variety or pieces?

However, the cambridge dictionaries online gave these confusing examples which don't support my distinction above.
- dress fabric
- cotton fabrics

Could someone please shed more light on this please? There are also millions of examples like this and any pointers as to how we can easily distinguish between the two would greatly be appreciated because dictionaries don't often make such distinctions, as mentioned. VERY MANY THANKS

[Tdol]

fabric = a material - a concept and hence uncountable and shouldn't be pluralized
fabrics = different types of fabrics? stressing the variety or pieces?

[Tedwonny]

Thanks for your reply

How then can I understand
- dress fabric
- cotton fabrics
The two examples given by the dictionary?

Many Thanks

[Tdol]

1- Material used to make dresses (not suits)
2- There are different types of fabric made from cotton- pure/mixed/easy iron, etc.