Loosely defined, a Schwarzschild radius is a point where a sphere is forced to become a black hole. The term Schwarschild is a portmanteau of two German words: Schwarz, meaning "black", and schild, meaning "shield", which makes sense. Schwarz, through Middle German swarz, Old High German swarz, and Proto-Germanic swartaz, comes from the Proto-Indo-European root swordo, meaning "black". Very little semantic change for that term. Schild, through Middle German schilt and Old High German scilt, comes from the Proto-Germanic word skelduz, which also meant "shield" and is the etymon of the English word shield, by way of the Old English word scild. Skelduz is from Proto-Indo-European skel, which meant "to cut", under the connection that you cut wood to make a shield. So, now we know how Schwarzschild came to mean "black shield". HOWEVER, that was all just the last name of Karl Schwarzschild, a German physicist who first theorized the radius. This may be the single most incredible coincidence in all of scientific etymology and is amazing
Adam Aleksic, a leading contender for valedictorian of his high school, is a 215-month-old boy with disturbing interests in etymology, vexillology, geography, and law. Adam would like to one day visit Tajikistan and probably isn't spying for the Uzbek government.
The Etymology Nerd