RO, The ISO 3166-1 alpha-2 country code for Romania

ro, the ISO 639-1 alpha-2 code for the Romanian language

Ragnarok Online, an MMORPG

Junior Reserve Officers' Training Corps (JROTC)

Read-only memory (ROM), a type of storage media

Reserve Officers' Training Corps (ROTC)

Receive only, a type of teleprinter that contains neither a keyboard nor punched tape equipment

Reverse osmosis, the process of pushing a solution through a filter that traps the solute on one side

Read-only access to files or directories in file system permissions

RO, the IATA code for TAROM, the flag carrier airline of Romania

Regnum Online, an MMORPG

RO Renewables Obligation

Red Orchestra: Ostfront 41-45, a WW2 realism based online FPS based on the Unreal Engine

Red Orchestra (spy), a Soviet operation during World War II

Reach Out, an Australian website created to help young people through tough times

Ro Laren, a character in the Star Trek series

Relaxation oscillation

Royal Ordnance, a British arms manufacturer, which is now part of BAE Systems Land Systems

Autoantigen Ro, also known as Calreticulin

Red Orchestra: Combined Arms, a first-person tactical shooter total conversion for Unreal Tournament 2004

Ro (language), an artificial language created by Edward Powell Foster

Rho (upper case Ρ, lower case ρ) is a letter of the Greek alphabet. See Rho (letter). The lower-case letter rho (ρ) may...

Ro (pharaoh), an early pharaoh

Ro (kana), Japanese kana

Ro (title), a title of nobility in Fiji

Ro, Italy, a city in the province of Ferrara, Italy (not to be confused with Rho, Italy)