rub

Rub refers to the act of applying pressure and friction by moving one surface against another. As a verb, to rub means to move back and forth or in a circular motion with contact between surfaces for cleaning, warming, polishing, or soothing irritation. As a noun, a rub can be a friction motion, a mark left by rubbing, or a problem or snag in a plan, often described with the phrase there is a rub.

Rubbing is used in daily activities such as cleaning and skincare, in massage, in polishing objects, and in medical contexts for disinfection with rubbing alcohol. The effect of rubbing depends on pressure, duration, and the materials involved; excessive friction can irritate skin or wear down surfaces. Common rubbing implements include hands, cloths, brushes, and pads. Idioms such as rubbing someone the wrong way and there is a rub reflect metaphorical uses of friction.

Etymology and related terms: The verb comes from Old English rubban, with cognates in other Germanic languages; the noun sense derives from the action. In various languages, similar roots describe friction or abrasion. The basic concept is a simple physical interaction shared across cultures.

Rub may also refer to the ruble, the currency of Russia and some neighboring states. The ISO 4217 code is RUB, and the symbol used in some contexts is ₽. The ruble has a long history of reforms and economic changes and remains a major currency in the region.