When you get out of the shower, the first thing you do is grab a towel and dry off. A towel is a piece of material that's used to absorb moisture.
Towels come in many sizes and styles, from enormous terrycloth beach towels to sheets of paper towel you use for wiping up kitchen spills. What they have in common is absorbency—they're made to soak up liquids. You can also use towel as a verb: "The dog is soaking wet! Towel her off before you let her on your bed!" And when you've utterly given up on something, use the boxing-related phrase "throw in the towel."