10 letters · 14 points in Scrabble
originCoined by American journalist and editor Sylvia Wright in 1954 in Harper's Magazine from mishearing a line in the Scottish ballad The Bonnie Earl o' Moray: “They have slain the Earl o' Moray, / And laid him on the green”, the second line being misheard as, “And Lady Mondegreen”.
Etymology from Wiktionary, CC BY-SA 3.0