zori is a Japanese word. According to my dictionary zo means grass and ri means sole. They're also sometimes called "flip-flops" because of the sound they make.

How to run in zoris:
Because zoris flop around loose on your feet, it is hard to run in them. The secret is to curl your toes in just a little to force the zoris to stick to the soles of your feet. Unfortunately when you do this, the zoris no longer make that pleasant "flip-flop"-sound. Remeber, only curl your toes a little because if your curl them in too much, you stop running and start pirouetting which, as any dancer will tell you, hurts like hell.