penumbra
/pɪˈnʌmbrə/noun
(pl. penumbrae /-briː/ 或penumbras)
1- the partially shaded outer region of the shadow cast by an opaque object（不透明物体投射的）阴影的外围半阴暗部分。
1.1
- Astronomy the shadow cast by the earth or moon over an area experiencing a partial eclipse【天文】（日食、月食的）半影。
1.2
- Astronomy the less dark outer part of a sunspot, surrounding the dark core【天文】半影（太阳黑子周围较淡的部分）
1.3
- any area of partial shade半阴影。
派生词
penumbral
adjective词源
mid 17th cent.: modern Latin, from Latin paene 'almost'+umbra 'shadow'.