Proper noun
the KISS principle
The empirical principle that most systems will work best if they are kept simple rather than made complex.
Pit & Quarry, Vol. 63, July 1970, p.172, quote: "as in every other step of the development process, follow the KISS principle — Keep It Simple, Stupid." Source: Internet
The KISS principle states that most systems work best if they are kept simple rather than made complicated; therefore simplicity should be a key goal in design and unnecessary complexity should be avoided. Source: Internet
The term "KISS principle" was in popular use by 1970. Source: Internet