to rub - a) to move one's hand, a cloth, etc. over (a surface or object) with pressure and friction, in a circular or back-and-forth motion; b) to move (one's hand, a cloth, etc.) over or spread or apply (polish, etc.) on or over, a surface or object in this way; c) to move (a thing) against something else or move (things) over each other with pressure and friction; d) to apply pressure and friction to, for cleaning, polishing, smoothing, etc.