Why this word is great
OBUMBRATION — [Noun] The act of darkening or obscuring; a shadowing over. From the Latin obumbratio ("a shadowing over"), from obumbrare ("to overshadow"), combining ob- ("over") and umbra ("shadow"). Unlike "adumbration" (which sketches a faint outline) or "penumbra" (which lingers in partial shade), obumbration is total eclipse—the moment when the last sliver of light is swallowed. It is the sudden hush of a room when the storm clouds blot the sun, the ink spilled across a page until the words vanish, or the way grief, when it comes in full, does not hint or hesitate but simply extinguishes. Some darknesses are not gradients; they are thresholds.