Of Celtic origin (see Muireall). Forms of the name are found in Breton as well as in Irish and Scottish Gaelic, and in the form Meriel it was in use in the heart of England in the Middle Ages. The surname Merrill is derived from it. As Muriel it was at first used mainly in Scotland, but became more widely popular during the first half of the 20th century. Since then it has fallen from favour again.
English: habitational name from any of various places in England so named, especially the one in Northumberland, which, like that in Cheshire, is derived from Old English geryd ‘channel’ + lēah ‘wood’, ‘clearing’. Those in Essex and Kent appear in Domesday Book as Retleia and Redlege respectively, and get their names from Old English hrēod ‘reed’ + lēah.