adj.本影的；有荫影的；阴暗的
umbral glaive───格拉维门槛
The six elements are manifest in all things great and small, and their polarity deriveth from the Astral heavens above and the Umbral depths below.───所有对象都会受到这六种元素得影响，而星灵属性的存在会增复或是削弱他们的影响力。
Pictured above, the face of a full moon is partly blocked by Earth's clouds, and partly darkened on the upper right by Earth's umbral shadow.───上图中，月亮被云遮去了一小部分，但是右上角的暗影并不是云造成的，那是地球的影子。
During totality, the Moon tracked through the northern part of the Earth's dark umbral shadow, so the southern half appeared considerably darker than the northern part.───月全食的过程中，月亮会经过地球本影的北部，因此月亮下半部分会比上半部分暗一些。
The path of the Moon's umbral shadow begins in India and crosses through Nepal, Bangladesh, Bhutan, Burma, and China.───月球阴影的路径开始于印度，紧接着穿越尼泊尔，孟加拉共和国，不丹，缅甸和中国。
Though the umbral magnitude is small, some regions of the moon will still be visible.───虽然蚀分不大，仍可看到月球部分区域的景象。
Causes and Preventive Measures of Umbral Lines on Stripy Fabrics with Polyester and Cotton Blended Yarns───涤棉混纺条形织物阴纹疵点的产生原因及其预防
A Probabilistic Interpretation to Umbral Calculus───哑运算的概率解释
A note on umbral calculus───关于哑演算的一点注记