The term 'Instrument for an Angel' can be broken down into two crossword solutions: LYRE (4 letters) and HARP (4 letters). Both of these instruments are stringed instruments that have been used for centuries in various cultures. The LYRE is a small, U-shaped HARP that originated in ancient Greece and was often used to accompany singing and poetry. The HARP is a larger instrument with a triangular frame and multiple strings that is believed to have originated in ancient Egypt. Both instruments are still used today in various forms of music and entertainment.