the implementation of a standard to be used as a definitive interpretation for the requirements in that standard. Reference implementations can serve many purposes. They can be used to verify that the standard is implementable, validate conformance test tools, and support interoperability testing among other implementations. A reference implementation may or may not have the quality of a commercial product or service that implements the standard.
Source(s):
NISTIR 8074 Vol. 2
under Reference implementation