The term 'LA-LA LEAD-IN' is composed of three words: SHA, TRA, and OOH. SHA stands for 'shave and a haircut', which is a traditional American song and jingle used as a call-and-RESPONSE phrase. TRA stands for 'two bits', which is an old-fashioned phrase used to refer to a quarter of a dollar. OOH stands for 'RESPONSE', which is the RESPONSE to the phrase 'shave and a haircut'. Together, these three words form the phrase 'LA-LA LEAD-IN', which is a popular phrase used to introduce a song or performance.