Not easily defined as it turns out.
Because a dictionary definition assumes that reality simply IS, and is unequivocally real.
Except that it isn’t
In fact, reality is so subjective and personal as to be something different entirely.
Different that is from an assumed definition at the tail end of an internet search.
For the “mad” homeless person on the street, reality is whatever his mind perceives.
I once knew a street dwelling old man named Fritz who spoke as if he was in high school. He told me of basketball games and class and the like. To me it was obvious he was not actually a sixteen year old high school basketball player, but in his mind and his reality it was so.
Who then are we to assume we can pinpoint any one reality?
Reality it seems is deeply personal and a direct function of the mind.
A miraculous and vexing piece of machinery.
Or perhaps not a machine at all but an energetic force, the capabilities of which we have yet to fully grasp.