noun
penumbra
puh-NUM-bruh/pəˈnʌmbrə/
An area of partial shadow surrounding a darker shadow.
A soft penumbra surrounds the darker center of the shadow.
Etymology
“Almost” plus “shadow” describes a region that is shaded only partly. In an eclipse, this is the lighter shadow surrounding the region of complete shadow.
In context
During this event, only a part of the moon enters the darkest portion of Earth's shadow, while the rest remains in the fainter penumbra.
More examples
- The moon dims as it enters Earth's penumbra.
- The broad lamp creates a penumbra around the vase's shadow.
- The diagram shows a pale penumbra surrounding the dark central shadow.
Forms
penumbra · penumbras · penumbrae
penumbral adjective — Relating to an area of partial shadow.
Similar words
- shadow
- Shadow includes both fully dark and partly shaded areas.
- umbra
- Umbra is the fully shaded center, not the partial shadow.