My mom always said there were three types of friends: those for a season, those for a reason and those for a lifetime.

When we were little, these categories didn't matter. A friend was just someone to play Barbies and swing on the swing set with.

We didn't analyze the dynamics of our relationships or wonder how long they would last. Our friends were just people to entertain us; people our parents might have chosen.

As we got older, though, we began to choose our own friends. And those friendships have become infinitely more important - especially the real ones; the ones we know in our gut will last a lifetime.

As we get closer to being flung out into the cold, dark, real world, we have to start sculpting our lives to fit us - doing what we want to do and not worrying about others.

This means that we may end up at a job in a strange city, far from anyone we know or love. We'll start surrounding ourselves with friends who are really just acquaintances, people to talk to at work and have a drink with on the weekend.

We won't have the time to fill them in on the last 10 years of our lives, or to spend hundreds of hours helping them memorize every crevice of our personalities.

So, they'll become the friends for a reason or a season, the friends who haven't watched us change and grow.

They'll never be the friends who'd understand the significance of us eating an escargot because they never saw us eat only pizza and mac n' cheese for the past 10 years of our lives.

We'll begin to hold our lifetime friends closer than ever.

This is a thank you to those friends we don't see for weeks or months on end and who can still finish our sentences as soon as we see each other.

Those friends who can tell just from the look on our faces what we're thinking - if we need to be reminded of that tear-inducingly funny inside joke, or if we just need a hug that means everything's going to be okay.

This is a thank you to those friends who make us seriously wonder whether we were related in a past life, because we are that eerily similar. With whom we never have to say, "Remember when?" because we're both already remembering.

The friendships whose mere existence makes us feel less alone, even if we're 3,000 miles away from that person. The people who, through the seemingly bottomless tears of an agonizing heartbreak make us think: Well, at least I still have them.

Thank you for being there when other friendships fall away. For being that constant presence, even when we have our own separate schedules that don't include the other.

For being so much more than just that drinking buddy or someone to go to D-hall or get coffee with.

For teaching us what friendship is about, and being a part of what makes us who we are.

Thank you, when we see each other after a long time apart, for giving us that feeling that yes, we're finally whole again.

ALSO ON THE COLLEGIAN