A half shadow. The partially shaded outer region of the shadow cast by an opaque object. Also, A peripheral or indeterminate area or group.
Mid 17th century: modern Latin, from Latin paene ‘almost’ + umbra ‘shadow’.
“As I dodged the heat of the day, standing in the penumbra of the large mansion house.”
“The problem is the penumbra of theory expands the potential answer too greatly.”
A custom, principle, or belief distinguishing a particular class or group of people, especially a long-standing one regarded as outmoded or no longer important.
Mid 17th century: from Hebrew šibbōleṯ ‘ear of corn’, used as a test of nationality by its difficult pronunciation (Judg. 12:6).
A conference or meeting to discuss a particular subject./ A collection of essays or papers on a particular subject by a number of contributors.
Late 16th century (denoting a drinking party): via Latin from Greek sumposion, from sumpotēs ‘fellow drinker’, from sun- ‘together’ + potēs ‘drinker’.