The term 'customers collectively' can be summarized as 'CLIENTELE', which is a 9-letter word. CLIENTELE refers to a group of customers or patrons who regularly purchase goods or services from a particular business. It is also used to describe the people who are associated with a particular artist, writer, or performer. CLIENTELE is an important factor in the success of any business, as it helps to ensure that the business has a steady stream of customers.