1. A trademarked adhesive powder, paste, or aerosol spray used in sports to improve athletes' grip on various pieces of equipment, such as balls, bats, dumbbells, etc., though its use has been banned in most professional sports. The term has become so ubiquitous in sports that it is often left uncapitalized. The wide receiver was accused of using stickum on his gloves in the championship game. I find I can lift much heavier weights when I spray a little stickum on the bars.

2. slang Any adhesive, such as glue. He had so much stickum in his hair that not even a tornado would have mussed it up! I hate running my fingers through his hair because they come out covered in stickum.

3. slang Any hair product, especially oil or pomade, used to slick one's hair down or hold it in place. He had so much stickum on his hair that not even a tornado would have mussed it up! I hate running my fingers through his hair because they come out covered in stickum.