The use of the term Proof of Concept goes back to at least 1984: https://en.wikipedia.org/wiki/Proof_of_concept#Usage_history https://en.wikipedia.org/wiki/Proo

The use of the term Proof of Concept goes back to at least 1984: https://en.wikipedia.org/wiki/Proof_of_concept#Usage_history https://en.wikipedia.org/wiki/Proof_of_concept#Usage_history I'm less clear on when PoC came into vogue, but I think it was likely in the 90s. Edit: Actually, reading more carefully, you can find "proof of concept" at least as far back as 1967.