What is Customer ?
Customer is (noun) 1. a person who buys something in a shop The shops are lowering their prices to attract customers. She was locking up the shop when a customer came in. His shop is always full of customers. 2. a person who uses a service such as a train We apologise to customers waiting on Platform 5 for the late arrival of their train.
source: Easier English, Student Dictionary Upper Intermediate Level