isnt it french?
Latin originally, for "the".
All the Romance languages use it or variations of it for "the".
Streetpass is when you are near someone else who has a 3DS and you get to play games with their mii in the mii plaza. And some games use streetpass to allow you to fight a bot with their items or send you their high score or something.
In order to streetpass someone, both 3DS systems must be in sleep mode. While the systems are communicating, their mii appears in your mii plaza to play games and things.
It is also used for non Mii Plaza games.
For example Animal Crossing: New Leaf sends a copy of your house to people you streetpass and vice versa for you to check out, and also buy items from.
And Pokemon Mystery Dungeon uses it to provide items to strangers.
Plus Pokemon X/Y uses it for something I can't recall.
There are a whole bunch of games which utilise it in some way or another, plus 3DS apps, like Letterbox (although that might have changed after the whole Letterbox kerfuffle. Not sure).
