An appreciation of friends

So yeah...been a while since I had the time and wherewithal to write a blog entry. 
I had an interesting conversation with my daughter today about friendships--interesting questions.

How do you define friendship?  Can it be defined--or is it "it just is".  
Does age matter?  Does gender?
Can you stay friends with people you've dated or "liked"?

The funny thing is I know a -ton- of people, I'm friendly with about 98% of those and at one level those are 'friends'.  There's not a word to describe them other than that--and they are people I DO care about--past players and coaches (Laura, Kelly), some former students and a couple staff from Satan's School for Girls and Boys, the people I work with at Lincoln Land, etc.

But then there's an inner circle of friends--for lack of a better way of putting it.  I think that that's a function of time as much as anything else.  When I look at that inner circle, the length of time I've known those people tells a tale:
Baron:  40 years
Dave:   29 years
Erik:     30 years
Eric:     39 years
Larry:   32 years
(And then the 'youngster'--Mrs. Dietz):
Julie:    24 years

And none of that is meant as a slight to other good friends--it just shocked me how long I've known the friends closest to me--which is probably a function of everyone getting older, I suppose.  But how do you explain that to your daughter--someone who hasn't been alive half as long as some of those friendships have existed?  Since she went to Uni--she's only really known the same set of people for 4-5 years....no friendship can run that deep when it's such a short amount of time.

I think that is especially important with dating relationships--now that I'm older and MAYBE wiser.  Kids always seem to think they have a perfect relationship, everything's so intense because it's all new--but only time can assure the friendship sticks, puts down roots so to speak for the long run.  I want to laugh--because I suspect my mom understood that even though it was never discussed.  So now I have to wait 15/20/30 years before my kids go "Hey, dad..." with an insight into friendship...and then I can whip out a link (or whatever we'll do in 2044) to this and say, "Ah, hah!" and point out my wisdom for their benefit.

All that's a long way around saying I'm blessed with a great circle of friends.  I should probably tell them they are appreciated more often--then again, that'd probably get me ridiculed and taunted (I've known these guys a long time...)

But really--how do you define friendship, something unique in a relationship between two people?