- A commonly used abbreviation for root mean square, a concept that comes up in subjects such as statistics and electronics.
- The initials and handle of free software guru Richard Stallman. (He is perhaps better known by his initials than his name.)
- An abbreviation for Royal Mail Steamer, for example the RMS Titanic. Different from His/Her Majesties Ship which is a title reserved for commissioned warships, for example HMS Enterprise.
- An acronym for rate-monotonic scheduling, an scheduling technique in operating system design.