The term 'Sock Exchange' refers to a business model where people can trade their used socks for new ones. The two crossword solutions, BOUT (4 letters) and SCRAP (5 letters), are related to this concept. BOUT is a term used to describe a large quantity of items, such as socks, that are available for purchase. SCRAP, on the other hand, is a term used to describe the process of exchanging used socks for new ones. Together, these two terms provide an accurate description of the Sock Exchange business model.