A really close friend.

It is a combination of two words:
"apl" stands for "Amigos Para Life"
"bby" is a shortened version of the word "baby"

(aplbby can also be said as applebby, because of the similarities between "apl" and the word apple)

Note: Amigos Para Life, (apl) is a funner way to say Best Friends Forever (bff) without sounding like a valley girl.
Ryan: Arite im tired gnite applebby! E>
Kathryn: Ok, gnite aplbby ttyl bai!! <3
by VinellaThrilla September 29, 2009
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