Back in the days of college, long before Al Gore invented the Internet, in my lopsidedly analytical brain, I came up with several terms and phrases, representing different grades of friendships, with basic characteristics of each. Here's how it goes:
To me, this is someone that you recognize. You may not know their name, nor may you have even had any conversation. It may be as simple as a head nod or a token acknowledging smile.
This is someone you hardly know but have had a smidge of conflict with....AND you worked it out. Emphasis is on the working things out.
This is deeper. The conversations have gone beyond the surfacy and there have been conflict / confontation that gets discussed and overcome.
This adds the time element and lots more interaction, seeing the best of times and the worst of times.
Add to that the spiritual element... praying with one another. Total trust.
Mind you, we're talking about nice, neat categories and people, here, so not everyone and everything can be pigeon-holed. I realized that this is just a useful tool and need be taken with several grains of salt.
And since this was in the days before Internet, it didn't take into consideration cuber friends, of which, at least two people I know have termed as not being real friends, mainly because of having never actually met them.