Trap: An opening in the stage floor, usually protected by a hinged or sliding cover. In the 19th century, traps were also built vertically into walls, to permit sudden disappearances and appearances (cf. The Vampire, Planché, 1820)
Some thoughts on Traps in temporary venues
Traps require considerable room beneath the stage floor. While it is possible that a temporary stage, erected on the floor of a banqueting hall, might employ a trap, it seems unlikely. What evidence we have from the Inigo Jones productions suggests a typical stage height of about four feet above the floor of the banqueting hall, not enough room to permit an actor a graceful entrance from below.
To cut through the floor of a banqueting hall seems unlikely, the problems of restoring the cut being considerable. Consider, for example, Sir William Davenant at Lisle's Tennis Court. A search of the scripts associated with this theatre suggest that neither traps nor flying machinery were used during Davenant's tenure. Quarrè tennis courts of the period had slate floors, and it seems likely that Davenant had no desire to tear up such a floor when the lease specifically stipulated that the facility was to be restored to its original condition when vacated by the theatre company.
However, when the company moved to Dorset Gardens Theatre, built specifically as a performance facility, the performance record indicates that traps were employed lavishly. At Lisle's Tennis Court, for example, the Masquing scene in The Tempest, with its elaborate disappearing table, was not performed. At Dorset Gardens Theatre, however, this scene was restored, suggesting, along with similar evidence supplied by other productions, that at Dorset Gardens the stage was fully trapped.