• Radiant Dawn, a tactics, turn based strategy RPG for the Wii
• Radical Dreamers, a text-based role playing game on the Satellaview made in 1996
• Rd (digraph)
• rd, a shell command meaning "remove directory"
• Reader's Digest
• Real Drive, an anime by Production I.G
• Reasonable Doubt, rapper Jay-Z's debut album
• Reassurance Directional, a class of road sign that tells the driver how far away particular towns are along that route
• Red Destiny, a character in The Big O
• Registered Dietitian
• Retinal Detachment
• Resident Director, a common staff position at universities and colleges with on-campus housing
• Road, abbreviation
• Rocketdyne
• Ruby Document format
• Rutherford (unit), symbol of a unit of radioactivity
• Ryan International Airlines, IATA airline designators
• Radio Disney
• Rural Development, an agency of the United States Department of Agriculture
• Red Dwarf
• Reserve Decoration, an award for service in the Royal Navy Reserve
• Reservoir Dogs
• RD, a Soviet/Russian prefix for an engine design series, stands for "Reaktivniy Dvigatel" (literally, Reactive Engine), see RD-8 for example

See also

• Ordinal indicator for 3 (that is, "3rd"), also known as an "ordinal suffix"
• R&D, Research and development
• , Wikipedia:Reference desk