/ ˈfrɪkʃn; NAmE / 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 ] friction (between A and B) disagreement or a lack of friendship among people who have different opinions about sth
SYN tension :
conflicts and frictions that have still to be resolved
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WORD ORIGIN
mid 16th cent. (denoting chafing or rubbing of the body or limbs, formerly much used in medical treatment): via French from Latin frictio(n-) , from fricare to rub.