PENUMBRA n.
The shadow cast, in an eclipse, where the light is partly, but not wholly, cut off by the intervening body; the space of partial illumination between the umbra, or perfect shadow, on all sides, and the full light. Sir I. Newton.
PLUNGE n.
[Cant] Plunge bath, an immersion by plunging; also, a large bath in which the bather can wholly immerse himself. -- Plunge, or plunging, battery (Elec.), a voltaic battery so arranged that the plates can be plunged into, or withdrawn from, the exciting liquid at pleasure.
PUBLIC SCHOOL n.
In Great Britain, any of various schools maintained by the community, wholly or partly under public control, or maintained largely by endowment and not carried on chiefly for profit; specif., and commonly, any of various select and usually expensive endowed schools which give a liberal modern education or prepare pupil…