penumbra
noun /pəˈnʌmbrə/
/pəˈnʌmbrə/
(specialist)- an area of shadow which is between fully dark and fully light
- (astronomy) the shadow made by the earth or the moon during a partial eclipse compare umbraTopics Spacec2
Word Originmid 17th cent.: modern Latin, from Latin paene ‘almost’ + umbra ‘shadow’.