IPA: /ˈkʌstəmər/
KK: /ˈkʌstəmər/
A person who buys goods or services from a business.
The store always tries to satisfy every customer.
Customer → It is formed from "custos" (meaning guard or keeper) and the suffix "-mer" (from Latin "mereri", meaning to earn or deserve). The word originally referred to someone who is a keeper or guardian of something, evolving to mean a person who purchases goods or services.
Think of a 'keeper' ('custos') who 'earns' ('mereri') by buying things — that's how a customer is someone who buys goods.