I read in this comment from @niftynei a very good analogy for the name 'lightning'. Like real lightning, which simultaneously tries all paths to find the one with the least resistance, the lightning network does the same with pathfinding. Additionally, once a path is found, a lightning strike actually travels from the ground to the sky—just like how preimages are released from the receiver to the sender. Pretty cool, actually.

Thought I'd share this here.