Standard (S): A precise statement of a set of requirements to be satisfied by a material, product, system or process that also specifies the procedures for determining whether each of the requirements is satisfied.  

Standard Test Method (STM): A definitive procedure for the identification, measurement and evaluation of one or more qualities, characteristics or properties of a material, product, system or process that yield a reproducible test result.  

Standard Practice (SP): A procedure for performing one or more operations or functions that may or may not yield a test result.  Note, if a test result is obtained it is not reproducible.  

Technical Report (TR): A collection of technical data or test results published as an informational reference on a specific material, product, system or process.