Oxford Dictionary English customer base nounnoun BrE BrE//ˈkʌstəmə beɪs// ; NAmE NAmE//ˈkʌstəmər beɪs// [usually singular] (business) Add to my wordlistjump to other resultsall the people who buy or use a particular product or service We need to appeal to a wider customer base. Her company has built up a customer base of 90 000.See customer base in the Oxford Advanced American DictionaryCheck pronunciation: customer base oxfordlearnersdictionaries.com