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.
Spanish, Portuguese, and Jewish (Sephardic): habitational name from any of numerous places in Spain and Portugal called Miranda. The derivation of the place name is uncertain; it may be of pre-Roman origin, or from Latin miranda ‘view’, ‘outlook’. This name is also found in western India, where it was taken by Portuguese colonists.