What is a "reference" system?

When I was in high school my reference system was the AM radio in the dashboard of a '50 Ford driving eight speakers stolen from drive-in movie theaters.

@fastfreight 

like most things in audio, it’s a bs term, loaded with subjectivity.  To me it means the most in the context of a professional reviewer.  As in “…compared to my reference DAC, DAC X sounds…”

A "reference" system is your stereo system at home home that you reference when you are unsuccessfully trying to hit on that hot blonde at the bar. Seriously, it is a system so resolving and familiar to the owner that he can swap in a single piece of gear and immediately hear the differences in its sound quality from the piece that it replaced.

My reference system is my reference system. 

i dont know why so many people have jammed this up with BS answers. its VERY SIMPLE. there is NO AMBIGUITY to its meaning. 

an incredibly transparent, revealing system with  the highest  fidelity that acts as a standard for comparison (reference) for all other audio systems and media. 

in other words, the standard is so high that it its fidelity is more like a calibrated measuring device than a not. 

the phrase "reference system" can be used however one wants, but that doesnt mean its correct.