齒
The story of 齒
tooth
齒 depicts a grinning mouth which showing the teeth inside. The upper part of 齒 is 止, which indicates the pronunciation of 齒, since both 止 and 齒 share the same pronunciation(zhi3), when you say 齒, you grin and show your teeth. On the other hand, a row of teeth looks similar to a row of toes.