A standard is a document that specifies requirements for products, services and/or processes, laying down their required characteristics.
Standardization promotes efficiency and quality assurance in industry, technology, science and the public sector. Standards are nothing more, and nothing less, than doing things a consistent way. They are used to ensure that products are made reliably, are repeatable, and adhere to safety laws and regulations.
Standards are developed by those who have a need and an interest in using them. NASA is an example of it. There are many different, comprehensive, and sophisticated standards used in Aerospace Industry. While some of them are about management systems standards such as ISO 9000 and AS 9100,