Zhuangzi glossary

 

罔兩

Penumbra

The blurry edge or partial shadow surrounding a full shadow.

See

video for more about shadows.

Where the light source is completely blocked = umbra

Partially blocked = penumbra

Where two penumbras merge = shadow blister

The antumbra (from Latin ante, "before") is the region from which the occluding body appears entirely within the disc of the light source.