The American Society of Mechanical Engineers (ASME) defines a standard as "a set of technical definitions, instructions, rules, guidelines, or characteristics set forth to provide consistent and comparable results, including:
Items manufactured uniformly, providing for interchangeability
Tests and analyses conducted reliably, minimizing the uncertainty of the results
Facilities designed and constructed for safe operation."
Learn about the importance of standards from these short readings:
Standards Overview from NIST -- the National Institute of Standards and Technology
What are standards? Why are they important? From the IEEE Standards Association.
Many organizations create standards -- IEEE and ASTM are two important standards organizations for mechanical engineering students to know about. Government agencies such as NASA and the military also develop standards. Some standards are easy to obtain -- others are more difficult. If you need help finding a standard, ask a librarian.