Definition of the word penumbra

The word "penumbra" comes from the Latin word "penumbrā" which means "shading" or "shadowy outline." It is a scientific term used to describe the partial shadow that is cast by an object, such as the moon during an eclipse. The term "penumbra" is derived from the Greek words "pēnē" meaning "almost," and "umbrā" meaning "shadow." The penumbra is different from the umbra, which is the dark central shadow of the eclipse seen near the edges of the eclipse. The penumbra is less dark and less distinct than the umbra and can often be hard to see. The penumbra is caused by the fact that not all of the eclipsing body, such as the Earth, comes directly between the sun and the moon, which creates a slight overlap that results in a partial eclipse.