The dress rehearsal is a full-scale rehearsal where the actors and musicians perform every detail of the performance. For a theatrical performance, actors wear their costumes. The cast members may use props and backdrops; they do not use scripts, though the stage manager and director might. AN 'open-dress' is a dress rehearsal to which specific individuals have been invited to attend as audience members.
In theatre a performing arts ensemble rehearses a work in preparation for performance before an audience. Rehearsals that occur early in the production process are sometimes referred to as 'run-throughs'. Typically a run-through doesn't contain many of the technical aspects of a performance, and is primarily used to assist performers in learning dialogues and to solidify aspects of blocking and stage movement.
A Q-2-Q or 'cue to cue' is a type of technical rehearsal and is intended primarily for the lighting and audio technicians involved in a performance, although they are of great value to the entire ensemble. It is intended to allow the technicians and stage manager to rehearse the technical aspects of a performance - when lights have to be turned on, sound effects triggered, and items rolled on and off the stage - and identify and resolve any glitches that may arises. Performers typically do not rehearse entire scenes during a Q-2-Q, but instead only perform dialogues or actions that are used by the stage manager as a marker for when to initiate technical sequences of cues.