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pentazocine
Pentecost
Pentecostal
Pentelic marble
pentene
penthouse
pentimento
Pentland Firth
pentlandite
pentobarbital sodium
pentobarbitone sodium
pentode
pentosan
pentose
pentose phosphate pathway
pentoxide
pentstemon
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penumbra

pe·num·bra [ pə númbrə ] (plural pe·num·brae [ pə núm bree ] or pe·num·bras)


noun 
Definition:
 
1. partial shadow: a partial outer shadow that is lighter than the darker inner shadow umbra, e.g. the area between complete darkness and complete light in an eclipse

2. indeterminate area: an indistinct area, especially a state in which something is unclear or uncertain

3. periphery: the outer region or periphery of something

4. astronomy edge of sunspot: a grayish area surrounding the dark center of a sunspot

[Mid-17th century. < modern Latin< Latin paene "almost" + umbra "shadow"]

pe·num·bral adjective
pe·num·brous adjective
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