The term originated with draw poker, and is really meaningful only in that game where the distinction between an outside and inside draw is critical--outside draws are sometimes playable and inside draws rarely if ever are. But the term is also used in games like Texas Hold'em where it is less relevant, because many inside draws can be played profitably and some outside draws cannot be, other factors usually being more important.
Seven-card games like hold'em and stud also allow the possibility of double belly-buster draws, also called double-inside or two-way draws, which, like an inside draw, a card is needed within a series to fill. But unlike simple inside draws, two ranks can fill the hand. An example of this is A♥ 3♥ 4♣ 5♠7♣, in which a deuce fills the inside straight A2345, and a six would fill the inside straight 34567.
These terms are also used for straight flush draws. 2♥ 3♥ 4♥ 5♥ is a straight-flush draw, since A♥ and 6♥ will create straight flushes. Such hands are optimal drawing hands, since the player has up to fifteen outs (nine cards remaining in the suit, six cards which complete the straight but not the flush).
Categories: Poker gameplay and terminology