Betting two or three streets in a row.
Betting the flop and turn is a double barrel; betting through the river is a triple barrel. Example. AA bets the K♠ 8♦ 3♣ flop, then the turn and river: a triple barrel. Triple-barrel value is two pair or better, overpairs, and top pair against players who don't fold. Draws semi-bluff through the turn, and don't barrel bluffs against players who don't fold.