A hoof, or a nail or claw slightly hooked.

蹄甲。

The part of a cylinder, cone, or other solid remaining after the top has been cut off by a plane oblique to the base.

【数】(几何)蹄形体(圆柱、圆锥、或其他立体上以平面斜切后剩余之部分)；截头圆锥。