Other forms: collided; colliding; collides
It could be protons bouncing around in a particle accelerator, two cars failing to stop at an intersection, or the priorities of two people with very different goals. When things crash together, they collide.
The verb collide has roots in the Latin word collidere, which comes from col- or “together” and laedere, “to strike or damage," like planes that collide in midair. Collide can also describe ideas that clash, such as expectations that collide with reality or radical views that collide with tradition.