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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 ?
This is probably a sign that the object itself was not a collisional fragment.
As the primary emission process in the lower corona is collisional excitation, which increases rapidly with temperature and density, coronal holes, being less dense and cooler than their surroundings, emit less radiation and hence appear darker.
As so, Montasser tackled the collisional relation between art and religion in three articles this week, from a historical perspective all the way up to extremist approaches.
15) The preliminary study was based on plasma kinetics and made use of a quasi-linear approximation to the collisional Liouville equation to derive the distribution function, F (r, v), of brain activities in the neural phase space (i.
The Himalaya came into existence only at this collisional boundary.
The Dabashan thrust nappe structure at the southern margin of the Qinling orogenic belt suffered at least two stages of evolution which are Late Triassic plate subduction collisional orogeny between North China block, Qinling micro-plate and Yangtze block followed by intracontinental orogeny since the Meso-Cenozoic.
Mo, Proton-bound complex mediating retro-Michael-type fragmentation of protonated 3-substituted oxindoles in the Orbitrap high-energy collisional dissociation cell, Rapid.
The contributions that make up the main body of the text are devoted to spectroscopic imaging of strongly correlated electronic states, wave turbulence on the surface of water, collisional aggregation due to turbulence, and many other subjects related to condensed matter physics.
In a collisional or dynamic quenching the fluorophore and the quencher contact each other during the lifetime of the excited state, whereas in a static quenching a complex is formed between the fluorophore and the quencher.
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).
A seismic geotraverse across the Iberian Variscides: orogenic shortening, collisional magmatism and orocline development.
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