murk (n.)

"gloom, darkness," c. 1300, myrke, from Old Norse myrkr "darkness," from Proto-Germanic *merkwjo- (source also of Old English mirce "murky, black, dark;" as a noun, "murkiness, darkness," Danish mǿrk "darkness," Old Saxon mirki "dark"); perhaps cognate with Old Church Slavonic mraku, Serbo-Croatian mrak, Russian mrak "darkness;" Lithuanian merkti "shut the eyes, blink," from PIE *mer- "to flicker" (see morn). In Middle English also as an adjective (c. 1300, from Old Norse) and a verb. Sometimes spelled mirk, especially in Scotland. Mirk Monday was long the name in Scotland for the great solar eclipse of March 29, 1652 (April 8, New Style).