Box drum made entirely of wood including the "head" or playing surface. Originally from Peru & Cuba, now used extensively in Flamenco Music and in place of a drum set (kit) in "unplugged" rock & pop sessions. Cajon means box or drawer in Spanish.
Not to be confused with "cojones".
American Idol Katherine McPhee was accompanied by two cajon players during her performance of "Black Horse & The Cherry Tree".