Amazon sellers are businesses and individuals that sell products at Amazon. They can ship the products themselves or use the Fulfillment by Amazon program to fulfill customer orders. In addition, they’re the seller of record for a given order, taking care of customer service and returns. Sellers manage their inventory on Seller Central.
Amazon vendors are businesses that sell their products to Amazon. In turn, Amazon sells those products to customers and is the seller of record, handling everything from storage and shipping to customer service and returns. Amazon vendors manage their inventory on Vendor Central.