What is a technical standard?
Standardization in mechanical engineering

a standard is a "technical specification, or other publicly available document, established with the cooperation and consensus or general approval of all interested parties, based on the combined results of science, technology and experience, aimed at the optimum benefit of the community as a whole, and approved by a nationally, regionally or internationally qualified body".

A "technical specification approved by a recognized standardizing body for repeated or continuous application, compliance with which is not mandatory".