This name is used for all options with knock-in or knock-out barriers: They are basically Calls or Puts, but they can only be exercised if a barrier has / has not been reached anytime until expiry (American style). A very liquidly traded example is the Up-And-Out-Call, which has the same payoff as a plain vanilla Call if a barrier B has not been reached until expiry, otherwise the option expires worthless. In the European style - version the option can only be exercised if the barrier has / has not been reached at expiry.