friction

Universal Words noun 1 [U] the action of one object or surface moving against another: Friction between moving parts had caused the engine to overheat. 2 [U] (physics) the RESISTANCE (= the force that stops sth moving) of one surface to another surface or substance moving over or through it: The force of friction slows the spacecraft down as it re-enters the earth's atmosphere. 3 [U,C] ~ (between A and B) disagreement or a lack of friendship among people who have different opinions about sth: conflicts and frictions that have still to be resolved