— collisional , adj.
/keuh lizh"euhn/ , n.
1. 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.
[ 1400-50; late ME collision- (s. of collisio ), equiv. to collis ( us ) (ptp. of collidere to COLLIDE) + -ion- -ION ]