Antumbra

Part of speech: noun

Pronunciation: /ænˈtʌm.bɹə/

Definitions

1. The area of a shadow cast by a celestial body in which only a portion of the light source is obscured defines a specific zone during an eclipse that allows for the observation of the silhouetted object
2. This term describes the lighter part of a shadow surrounding the darker middle region that occurs when one celestial body partially occludes another
3. The region surrounding the darkest part of a shadow, where the light source is only partially blocked, can be observed during certain celestial events

Etymology: The word "antumbra" is built from two Latin parts: "ante," meaning "before," and "umbra," meaning "shadow." Latin "umbra" was the ordinary word for a shadow or shade, and the English term keeps that core image of a dark form cast by an object blocking light. The "ante-" in this formation points to position rather than time: the antumbra is the zone lying just in front of, or beyond the edge of, the main shadow. In an eclipse, the umbra is the dark central core where the light source is fully hidden, and the antumbra is the lighter outer fringe where the body only partly blocks the light. The sense of "before" here is spatial, marking a region that comes ahead of the full shadow as one moves outward from the centre.