dress rehearsal

Noun

dress rehearsal (plural dress rehearsals)

1. A rehearsal prior to a public spectacle, where all the performers are in costume, in order to test all aspects of the production by closely reproducing the actual conditions of a performance.
   • We've got three dress rehearsals before the opening night to prepare ourselves for any potential technical issues.
2. The final rehearsal before a performance, whether or not costumes or performance dress are worn.
3. (broadly) Any complex activity that serves to prepare for a more important iteration of it later.
   • Although the train derailment ended up not being very serious, the emergency services' response served as a dress rehearsal in case of a much worse disaster.
   • Sunday, November 6, was spent in a second full-scale dress rehearsal of the complete weekday electric timetable, [...] during which the public were invited to make their first trial of the trains—and 15,000 did so.1960 December, “The Glasgow Suburban Electrification is opened”, in Trains Illustrated, page 712