The term 'PIT TUBE' is a combination of two words, 'PIT' and 'TUBE'. The first word, 'PIT', refers to a deep hole or cavity in the ground, while the second word, 'TUBE', refers to a hollow cylinder or conduit. Together, they form a type of musical instrument known as an OBOE, which is a woodwind instrument with a double reed and a conical bore. The OBOE is used in many genres of music, including classical, jazz, and folk.