Definition of penumbra noun from the Oxford Advanced Learner's Dictionary



    BrE BrE//pəˈnʌmbrə//
    ; NAmE NAmE//pəˈnʌmbrə//
    (specialist) The sun and the moon
    jump to other results
  1. 1an area of shadow which is between fully dark and fully light
  2. 2(astronomy) the shadow made by the earth or the moon during a partial eclipse compare umbra See related entries: The sun and the moon
  3. Word Originmid 17th cent.: modern Latin, from Latin paene ‘almost’ + umbra ‘shadow’.
See the Oxford Advanced American Dictionary entry: penumbra