Curious about khas/khoshiya terms

This post may seem immature or a little stupid but I have seen these words in this sub a lot of times before and I am kind of curious what they mean. I am a teenager so I don't really know about this stuff and tried asking my parents but got no clear understanding.
Who are these people ? Why are they called so ? Am I one ? A lot of questions
also, I have never heard anybody else say these words before in my hometown or in Himachal in general.

Please enlighten me (in simple words if possible) , I would love to know more about my history and culture