The term 'sell door-to-door' can be summarized as peddling, which is a 6-letter word. Peddling is the act of selling goods or services directly to customers in their homes or other locations outside of a retail store. It is a common practice for salespeople to go door-to-door in order to reach potential customers and increase their sales. Peddlers often carry a variety of items such as books, magazines, clothing, jewelry, and other products. They may also offer services such as home repairs, lawn care, and cleaning. Peddling is an effective way to reach customers who may not otherwise have access to a retail store.