Either
a) A shortened version of 'best
friends' for internet talk.
or
b) Someone who is
really close to being categorized as a
best friend, but not exactly one yet.
a)
TTYL bestie! XOXOX lylas!
b) Jamie: You
know you're my bestie for life, girl. Arianna: WHAT, I'M NOT YOUR
BEST FRIEND!!?! WHAT KIND OF RELATIONSHIP IS THIS?