The name Muriel is a girl's name of Irish origin meaning "of the bright sea". Muriel and is often added to lists like Old Lady Names and discussed in our forums with posts like "Girls Makeover - Two Middles".
From the experts:
Once a poetic Celtic name, that of the angel who governs the month of June, Muriel became the mom or grandma on TV sitcoms. She does have literary cred via Edinburgh-born author Muriel Spark, author of The Prime of Miss Jean Brodie and also appears as a character in Anne of Green Gables. Muriel was a Top 200 name from 1912 to 1933.