From Middle English merke, mirke, from Old English mirce, myrce and Old Norse myrkr, both from Proto-Germanic *merkuz, from Proto-Indo-European *mergʷ-. Cognate Danish mørk, Norwegian mørk, Swedish mörk, Icelandic myrkur, as also Albanian murg, Proto-Slavic *morkъ, Lithuanian márgas, Ancient Greek ἀμορβός.
From Middle English mirke, merke, from Old English mirce, myrce and Old Norse myrkr, both from Proto-Germanic *merkwą, *mirkwiz, Proto-Indo-European *mergʷ-.
From Middle English mirken, probably from Old Norse myrkja, myrkva, from Proto-Germanic *mirkwijaną, *mirkwajaną, from Proto-Indo-European *mergʷ-.