Billy Joel is a famous American singer-songwriter and pianist. His instrument of choice is the PIANO, which is a five-letter word that was the solution to the crossword. The PIANO is a musical instrument that produces sound when its keys are pressed or struck. It is one of the most popular instruments in the world and has been used in many genres of music, from classical to jazz to pop. Billy Joel has been playing the PIANO since he was a child and has become one of the most successful and influential pianists of all time.