The term 'Clarinet Cousins' refers to two woodwind instruments, the oboe and the clarinet. Both instruments are members of the same family of instruments, known as double-reed instruments. The oboe is a five-letter instrument that produces a mellow, reedy sound. It is often used in classical music, but can also be found in jazz and other genres. The clarinet is a single-reed instrument that produces a bright, vibrant sound. It is commonly used in jazz, classical, and other genres. Together, the oboe and clarinet form a powerful combination that can be heard in many different types of music.