<I was merely looking to find out who uses or knows the word>

by, I don't know or use it, but I do quite happily use 'gsm' as a way to define paper 'quality' or thickness. This would equate to 'grams per square metre', or grammage, surely? It's what printers and publishers and stationers use as a standard in Oz at least, and from my vague recollections of time past also in other English-speaking countries.