My litmus test is "was it asked to be put there". I live in Denver and after we won the NBA finals a local artist put this up this[1] mural and it was coordinated with the business + building owner + local govt. I would call that a "mural" versus "graffiti". Now if you go out to our "warehouse district" you will often see "graffiti", that is stuff the owners never asked for, some kids just showed up and tagged the building in the middle of the night.

[1]: https://media1.westword.com/den/imager/u/magnum/17103041/ima...