Waffle, or sometimes honeycomb fabric is fabric, usually cotton or microfibre, woven in a way which makes it very absorbent. The waffle weave also allows air to flow through the towel so that it dries quickly.
Waffle fabric is used for cleaning surfaces in industry. The surface of the fabric is textured rather like an edible waffle, hence the name. This texture gives more surface area for absorption and cleaning than a normal flat surface. It is woven on a loom, and is therefore more durable than many chemically-produced fibres. It is not a mechanical or chemical process that can be washed off after thorough or heavy use.
Waffle fabrics are used for towels and bathrobes. Terry cloth is more often used for towelling.