What Are Standards?
Standards are documents created by professional and/or governmental organizations that contain technical definitions, specifications, and guidelines to ensure consistency, safety, and quality of materials, products, processes, and services.
The use of standards is voluntary, but encouraged in order to facilitate interchangeability across companies and support international trade.
Below is a promotional video for the International Organization for Standardization (ISO). It's a little heavy-handed, but does give a great visual of the application of standards in the products we use every day.
Source:National Institute of Standards and Technology; Office of Scientific and Technical Information