To come together with violent, direct impact.
To meet in opposition; conflict: "an unlikely foray by an industrial conglomerate into the terrain where entertainment and merchandising collide” ( Laura Bird).
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.