pe·num·bra
noun/pəˈnʌmbrə/
/pəˈnʌmbrə/
(specialist)- an area of shadow which is between fully dark and fully light
（黑暗与光明之间的）半影 - (astronomy) the shadow made by the earth or the moon during a partial eclipse
（偏食期间的）半影
Word Originmid 17th cent.: modern Latin, from Latin paene ‘almost’ + umbra ‘shadow’.