the act of colliding; a coming violently into contact; crash: the collision of two airplanes.
2.
a clash; conflict: a collision of purposes.
3.
Physics. the meeting of particles or of bodies in which each exerts a force upon the other, causing the exchange of energy or momentum.
Origin: 1400–50; late Middle English < Late Latin collīsiōn- (stem of collīsiō), equivalent to collīs(us) (past participle of collīdere to collide) + -iōn--ion