Definition, Meaning & Synonyms

umbra

noun

/ˈʌm.brə/

Definition

The fully shaded inner region of a shadow cast by an opaque object.

Examples

The umbra of the moon can create a total solar eclipse, where the sun is completely hidden from view.
During a lunar eclipse, the Earth’s umbra can cast a shadow on the moon, making it appear red.
The umbra is contrasted with the penumbra, which is the lighter part of the shadow where light is partially blocked.

Meaning

Umbra refers to the darkest part of a shadow, where the light source is completely blocked by an object. It’s often used in discussions about eclipses, where the umbra is the area where the sun is entirely obscured by the moon.