ro

RO is a two-letter abbreviation used in several distinct contexts, ranging from geography and linguistics to technology. It most commonly identifies Romania in official codes and is also associated with a well-known water-purification process. In computing contexts, RO can denote a read-only state. The overlapping uses reflect how compact acronyms can span domains.

Romania: RO is the ISO 3166-1 alpha-2 country code for Romania. It appears in the internet country code top-level domain .ro, on international vehicle registration plates as RO, and in sports rankings with the IOC code ROU. The country’s calling code is +40, its capital is Bucharest, and the official language is Romanian (language code ro). The currency is the Romanian leu (RON). Romania’s short-form representation in many international contexts is RO.

Reverse osmosis: Reverse osmosis is a water purification technology that employs a semipermeable membrane to remove ions, molecules, and larger particles from liquid. It is widely used in drinking-water treatment, municipal desalination, and industrial wastewater treatment. The process requires applying pressure to overcome natural osmotic pressure, driving water through the membrane while rejecting dissolved salts and contaminants. Typical configurations include pretreatment stages, a high-pressure pump, the membrane element, and post-treatment or polishing steps. Energy use varies with salinity, recovery targets, and membrane design, but RO is a common, scalable solution for producing high-purity water.

Other uses: In computing, RO commonly denotes a read-only state, such as mounting a filesystem as ro (read-only) or indicating that a device should be accessed without modification. In language codes, ro is the ISO 639-1 code for Romanian, reflecting its linguistic association with the country.