I recently learned of the series Trigun and, though I haven't started watching it yet, it seems quite interesting.
However, I'm curious about its title. "Tri-" seems to indicate "three", so I'd say the title meant either "three guns", or "gun with three parts" (like three barrels). However, I've only managed to find images of the main character holding one gun, or occasionally two, and nothing sticks out about them having three of anything.
Without spoiling too much of the plot's sensitive points, can someone explain why the series is called Trigun?