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.
PIGEON n.
Pigeon plum (Bot.), the edible drupes of two West African species of Chrysobalanus (C. ellipticus and C. luteus). -- Pigeon tremex. (Zoöl.) See under Tremex. -- Pigeon wood (Bot.), a name in the West Indies for the wood of several very different kinds of trees, species of Dipholis, Diospyros, and Coccoloba. -- Pige…
PILLOW n.
. -- Pillow bier Etym: [OE. pilwebere; cf. LG. büre a pillowcase], a pillowcase; pillow slip. [Obs.] Chaucer. -- Pillow block (Mach.), a block, or standard, for supporting a journal, as of a shaft. It is usually bolted to the frame or foundation of a machine, and is often furnished with journal boxes, and a movable c…