MUSICAL MAMA' Cass is a four-letter term that is used to refer to the musical mama, Mama Cass Elliot. She was an American singer and member of the 1960s folk rock group The Mamas & The Papas. She was known for her powerful and distinctive voice, which made her a successful solo artist after the group disbanded. Her most famous songs include 'Dream a Little Dream of Me' and 'Make Your Own Kind of Music'.