(automotive) A fixed or operable opening in a vehicle roof (car or truck) which allows fresh air and/or light to enter the passenger compartment. A sunroof may include a transparent or opaque panel...

It is sometimes necessary to cooperate with a person one does not like or agree with, in order to combat a common threat.

(medicine) Randomized clinical trial. / (statistics) Randomized controlled trial. / (military) Abbreviation of regiment(al) combat team.

the official administrative deputy of a regent; vicegerent