Other forms: rehearsals
A rehearsal is a practice performance before the real one — a play, a concert, a wedding. In rehearsal, a rehearsal room, the final rehearsal.
The dress rehearsal is the last one, done in full costume and as though it were the performance, and the phrase has escaped the theatre entirely: a dress rehearsal now means any full-scale practice run. The verb is rehearse, and it takes both an object and none: rehearse a scene, rehearse all afternoon. Note the second sense of rehearse, which is formal and means to go over something again in words: he rehearsed the same arguments for an hour.
1nounrehearsalA practice of a performance before it is given.
“The rehearsal ran three hours over.”
synonyms: practice, run-through
2nounfullA full practice of anything before the real event.
“The whole exercise was a rehearsal for the real evacuation.”
Too few real examples of this word to estimate which sense is commonest.
rehearsal is a practice run.
Old French rehercer meant to harrow again — to drag a rake over a field a second time, from herce, a harrow, which also gives hearse. A rehearsal is going over the same ground until it is properly broken up, which is exactly what a director is doing.
Middle French
rehercel
Middle English
rehercel
English, today
rehearsal
From Middle English rehercel, rehersail, rehersall, from rehersen and apparently partly Middle French rehercel. by surface analysis, rehearse + -al.
Etymology from Wiktionary, CC BY-SA