Also found in: Thesaurus, Medical, Legal, Idioms, Encyclopedia.


1. An act of colliding; a crash.
2. A condition of opposition or conflict between two or more people or things: the collision between management and labor.
3. Physics A brief dynamic event consisting of the close approach of two or more particles, such as atoms, resulting in an abrupt change of momentum or exchange of energy.

[Middle English, from Late Latin collīsiō, collīsiōn-, from Latin collīsus, past participle of collīdere, to collide; see collide.]

col·li′sion·al adj.
col·li′sion·al·ly adv.
Synonyms: collision, crash1, impact
These nouns denote violent forcible contact between two or more things: the midair collision of two planes; a crash involving two cars; a crater produced by the comet's impact.


of or relating to a collision or collisions
References in periodicals archive ?
In this regards, three mechanisms have been hypothesized [61]: 1) Hanle depolarization produced by random magnetic fields [57,71], 2) collisional depolarizations produced by hydrogen atoms (see [72] and references cited therein) and 3) radiation transfer effects (see [72] and references cited therein).
As a third unit, a chamber allowing determination of ion mobility (IM) will be integrated to determine collisional cross sections (CCS).
Our work indicates that Jupiter would have created just such a collisional cascade in the inner solar system," explains Laughlin.
Masson's French version fills out Kinsella's ellipses and resolves some of the perceptual indeterminacies that those ellipses generate so that the verse has a more measured pacing, a fuller rhythmic swell; inevitably, perhaps, Kinsella's rougher, more collisional thinking gives way to Masson's rhetorical, even Biblical, period.
The Maritimes Basin of Atlantic Canada: basin creation and destruction in the collisional zone of Pangea.
Convergence historyacross Zagros (Iran): constraints from collisional and earlier deformation.
Since then he has been involved in over 100 publications on Namibian geology, most notably editing a publication and map on the Pan African collisional Damara Orogen.
The resulting stress due to PP interactions determines the polymeric matrix rheological responses, CP exhibits the hydrodynamic (frictional) contribution in PNCs and CC represent the stress resulting from direct or collisional interactions between nanoparticles.
Earth's moon and the satellite system around Pluto are considered to be collisional byproducts.
More complicated models and new results follow, with a theory of gravitational encounters developed in some detail, loss-cone dynamics, collisional evolution of nuclei with perturbational and mass-driven expansion.
We report on new level-resolved calculations for the dielectronic recombination and collisional excitation of the low charge states of argon.
Full browser ?