The term 'HALF A SINGING GROUP' can be solved by the crossword solution MAMAS, which is a five-letter word. MAMAS is a reference to the popular singing group The Mamas and the Papas, who were an American folk rock vocal group that recorded and performed from 1965 to 1968. The group was composed of John Phillips, Denny Doherty, Cass Elliot, and Michelle Phillips. The Mamas and the Papas had several top 10 hits in the United States, including 'California Dreamin'' and 'Monday, Monday'. Therefore, the crossword solution MAMAS is a reference to half of the singing group The Mamas and the Papas.