friction

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The rubbing of one object or surface against another.
• noun Conflict, as between persons having dissimilar ideas or interests; clash.
• noun Physics A force that resists the relative motion or tendency to such motion of two bodies or substances in contact.

from The Century Dictionary.

• noun The rubbing of the surface of one body against that of another; attrition; frication.
• noun In mech., the resistance to the relative motion, sliding or rolling, of surfaces of bodies in contact: called in the former case sliding, in the latter rolling friction.
• noun Figuratively, lack of harmony; mutual irritation; worrying; difficulty.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of rubbing the surface of one body against that of another; attrition; in hygiene, the act of rubbing the body with the hand, with flannel, or with a brush etc., to excite the skin to healthy action.
• noun (Mech.) The resistance which a body meets with from the surface on which it moves. It may be resistance to sliding motion, or to rolling motion.
• noun A clashing between two persons or parties in opinions or work; a disagreement tending to prevent or retard progress.
• noun (Mech.) the angle which a plane onwhich a body is lying makes with a horizontal plane,when the hody is just ready to slide dewn the plane.
• noun (Mach.) wheels turning freely on small pivots, and sustaining, at the angle formed by their circumferences, the pivot or journal of a revolving shaft, to relieve it of friction; -- called also friction wheels.
• noun balls or rollers placed so as to receive the pressure or weight of bodies in motion, and relieve friction, as in the hub of a bicycle wheel.
• noun (Mach.) a form of dynamometer for measuring the power a motor exerts. A clamp around the revolving shaft or fly wheel of the motor resists the motion by its friction, the work thus absorbed being ascertained by observing the force required to keep the clamp from revolving with the shaft; a Prony brake.
• noun brakes attached to the common standing garrison carriages of guns, so as to raise the trucks or wheels off the platform when the gun begins to recoil, and prevent its running back.
• noun A toothed clutch, one member of which, instead of being made fast on its shaft, is held by friction and can turn, by slipping, under excessive strain or in starting.
• noun one in which the hammer is raised for striking by the friction of revolving rollers which nip the hammer rod.
• noun See Frictional gearing, under Frictional.
• noun an electrical machine, generating electricity by friction.
• noun an instrument for measuring friction, as in testing lubricants.
• noun a composition of chlorate of potassium, antimony, sulphide, etc, which readily ignites by friction.
• noun a tube used for firing cannon by means of the friction of a roughened wire in the friction powder or composition with which the tube is filled.
• noun (Mach.) one of the wheels in frictional gearing. See under Frictional.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The rubbing of one object or surface against another.
• noun Conflict, as between persons having dissimilar ideas or interests; clash.
• noun physics : A force that resists the relative motion or tendency to such motion of two bodies in contact.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun effort expended in moving one object over another with pressure
• noun the resistance encountered when one body is moved in contact with another
• noun a state of conflict between persons