A
dry run is an act committed by a
terrorist organization without carrying out any actual
terrorism in an attempt to determine whether a technique they are planning to use will be successful. The dry run is part of the rehearsal for a terrorist act, and is often the immediate precursor to the attack. It may include attempting to
smuggle weapons or other items to be used in the attack past a
security checkpoint to determine whether or not this will be noticed, or monitoring the reactions of security personnel to the actions that would occur during a real attack.