A force that needs to touch an object before it can affect it (e.g. friction).
a force which is applied while touching the object
A force which is applied by an object touching another object.
A contact force is a force that acts between two objects only when they are touching. What is a Force
A force between objects in contact with each other. A contact force can be attractive (as in a tension force), repulsive (as in a normal force), resistive (as in friction), restoring (as in a spring force), or arbitrary (someone pushing and pulling on things).
In physics, a contact force is a force between two objects (or an object and a surface) that are in contact with each other. This is distinct from a non-contact force (a force that acts over a distance), such as gravity or magnetic attraction/repulsion.