Bestfriends?

I was thinking about the word "bestfriends", what does it means, and who should i categorized in terms of "my bestfriends". What is the different between friends and bestfriends?
I have some kind of theory about this, i don't know if it is correct or not but gonna give it a go (please comment if i say something wrong :p)

here it go:
the equation in terms of his/her relationship with you
a person you know =< a friend =< a bestfriend

a person you know :
- a classmate
- a roommate
- someone from church
- someone from school
- etc (basically people you know and ever had a conversation with more then twice)

a friend is "a person you know" that:
- you care about
- you are comfortable talking and chatting with
- you like to know better
- you often spend time together


a bestfriend is "a friend" that:
- you treat like your own brother / sister
- treats you the same way
- that cares about you and understands you the most


well you can go on with the list but i really thinks that "my bestfriends" are the people who cares about me and understands me which i really consider as my brothers and sisters.

Now, in many verses in the bible Jesus consider us as a friend which means, He cares about us, He wants to know us better, He likes to spend time together with us and much more. That is why i consider Him as my bestfriend so that he will also consider me not just as a friend but as His bestfriend.