Definitions for "collider"
a particle accelerator in which two separate beams of particles (usually of opposite charge) are circulated in opposite directions and directed so as to collide head on. This technique allows the production of collisions of higher energy than would be possible with a single beam produced by the same device.
a big device (typically a few km long) that accelerates particles and smashes them on each other (they collide)
a high-tech machine used to generate interesting bits of matter by smashing together other not-quite-as-interesting bits of matter at extremely high speeds