The nouns client and customer are sometimes used interchangeably—especially by businesses seeking to show customers extra respect by referring to them as “clients”—but the words differ in their conventional definitions.
A client is someone who engages the services of a professional. For example, lawyers, plumbers, freelance writers, accountants, and web designers often work for clients. So these writers use the word well:
Provincial court Judge Brian Stevenson agreed with defence counsel Jim Lutz such a prohibition was warranted to preserve his client’s right to a fair trial. [Toronto Sun]
Brokers don’t have to act in a client’s best interest when dispensing advice, but a new study from the Securities and Exchange Commission recommends changing that. [The Baltimore Sun]
The agent for Carson Palmer reiterated Monday his client’s desire to part with the Bengals this offseason. [Rotoworld.com]
A customer buys goods or services from a business (rather than an individual or group of professionals). So it works well in these sentences:
Zappos.com and its parent, Amazon.com, provide the best customer service, according to a survey commissioned by the National Retail Federation Foundation and American Express. [The Consumerist]
Jim Carlson, the shop’s owner, referred to the man as a regular customer. [Duluth News Tribune]