A "mat towel" refers to a small, absorbent towel used during activities like yoga or exercise. It is placed on a workout mat to absorb sweat and prevent slipping. Full definition
A yoga mat towel will double as a blanket for the cold airplane flights and also be your slip free solution during sweaty yoga sessions. (gatheryoga.com)
Used to have to use mat towels in all my hot yoga classes but not with «the mat»! (olivesnwine.com)
I found the prettiest pillows in the home section and a yoga mat towel to boot for my hot classes all at killer deals! (looksforlovelies.com)