bufferable?

What does the term “bufferable” mean in the Shoryuken strategy guide for MK9?

I did a search and read 4 different explanations.

  1. The move can be cancelled (meaning the last frames of the animation) into another move?
  2. The move can be done by inputting the commands during a block?
  3. The move can be done by inputting the commands while your character is still completing another move?
  4. The move can be done by inputting the joystick movements after the attack button?

#3

As far as the other terms:
#1 is a “cancel”
#2 is mostly for capcom games. MK doesn’t have a buffer for reversals
#4 is much like #3, lots of combos involve buffering dash (forward, forward) this way while the move is still recovering from hitting the opponent

Yeah, 3 is the best explanation out of those as to what a buffer is. However I rarely find myself using them in this game.