Who coined the term “the lost generation”?

Gertrude Stein coined the term “the lost generation”.

She translated the phrase from a French garage proprietor who was angry at a young mechanic’s negligence in fixing Stein’s car.

Stein used it to refer to Hemingway and his contemporaries: “All of you young people who served in the war. You are a lost generation.”

The term came to mean the rootless, disillusioned generation that came of age between World War I and the Great Depression.