Main Entry: pen·um·bra

Pronunciation: \pə-ˈnəm-brə\

Function: noun

Inflected Form(s): plural pen·um·brae \-(ˌ)brē, -ˌbrī\ or pen·um·bras

Etymology: New Latin, from Latin paene almost + umbra shadow — more at umbrage

Date: 1666

1 a : a space of partial illumination (as in an eclipse) between the perfect shadow on all sides and the full light b : a shaded region surrounding the dark central portion of a sunspot
2 : a surrounding or adjoining region in which something exists in a lesser degree : fringe
3 : a body of rights held to be guaranteed by implication in a civil constitution
4 : something that covers, surrounds, or obscures : shroud <a penumbra of secrecy> <a penumbra of somber dignity has descended over his reputation — James Atlas>

— pen·um·bral \-brəl\ adjective