What is GSM? Rebecca Leonard July 04, 2019 08:18 Updated Follow GSM is an abbreviation for "grammes per square metre" and indicates how heavy a fabric is. When talking about towels, a higher GSM indicates a denser and fluffier towel that's more absorbent. Related articles What is the purpose/benefit of a Hammam Towel? Comments 0 comments Please sign in to leave a comment.