collision

Từ điển American Heritage Dictionary 4th

col·li·sion (kə-lĭzhʹən)n.
1. The act or process of colliding; a crash or conflict.
2. 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·liʹsion·al adj.col·liʹsion·al·ly adv. 
Synonyms: collision, concussion, crash¹, impact, jar², jolt, shock
¹ These nouns denote violent forcible contact between two or more things: the midair collision of two light planes; the concussion caused by an explosion; a crash involving two cars; the impact of a sledgehammer on pilings; felt repeated jars as the train ground to a halt; a series of jolts as the baby carriage rolled down the steps; experienced the physical shock of a sudden fall.