Perceived reality. Very theoretical, but on some base level it is very true.
Perception is divined to you by birth. You're parents and the entire subculture of your species does this, not only do you learn rudimentary bodily movements and eating habits; but you also inherit their perceptions. If I bore a child to this world and only allowed him to speak to me, I could in fact teach said child anything I wished.
I could make a fish a plane, a plane a rock, and trees into pets.
This is perceived reality, all baseline thoughts here can be reorganized though, through careful retraining of the mind. The only issue is that since we have no clue what is the "True" perceptive of reality and how it is named, we must simply default to was is most commonly accepted.
Think about it, right now had the word "Bitch" been turned into a name and not a vulgar word or slang term some time in our past... Your name could be "Bitch Jenkins".