PENUMBRA


Meaning of PENUMBRA in English

pe ‧ num ‧ bra /pəˈnʌmbrə, pɪˈnʌmbrə/ BrE AmE noun [countable]

[ Date: 1600-1700 ; Language: Modern Latin ; Origin: Latin paene 'almost' + umbra 'shadow' ]

technical an area of slight darkness

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.