Term - Coefficient of Friction
From VEX Wiki
A coefficient of friction is a constant which describes the "grippyness" of two surfaces sliding against one another. Slippery objects have a very low coefficient of friction, while sticky objects have a very high coefficient of friction. This constant is determined for a pair of surfaces, not a single surface, and ranges from near zero to greater than one. Each pair of materials has a coefficient of static friction and a coefficient of kinetic friction.
Do not confuse this with actual sticky surfaces like tape or high friction coatings that bind to the other surface. These surfaces almost need to be looked at as being joined together as one. For instance, tapes resist sliding even when there is no normal force (push down), or a negative normal force (pull up) when they are clearly not part of the other object.