What's the difference between a shower mat and a bath rug?

A shower or tub mat is a rubber, vinyl, or TPE surface designed to go inside the wet area, typically with suction cups, drain holes, or textured backing to prevent slips. A bath rug (often chenille or memory foam) is a soft absorbent mat for standing on outside the tub. Several popular listings blur the line, so check whether the product has suction cups and drain holes if you need genuine in-shower traction.