RI or ri may refer to: People Ri, a common Korean surname, a variant romanization of Lee Rí (rig), an ancient Gaelic word meaning "king" Ri (pronoun), a gender-neutral pronoun in Esperanto RI, an initialism of Rex Imperator (king-emperor) or Regina Imperatrix (queen-empress), used by those British monarchs who were rulers of both the United Kingdom and the Indian Empire Places Ri (administrative division), an administrative unit in both North Korea and South Korea Ri, Orne, a commune of the Orne département in France RI, abbreviation of either the Republic of Indonesia or, in the Indonesian language, Republik Indonesia Rhode Island, a state within the US (postal abbreviation RI) Arts and media Ri, an augmented second in solfege, used in music education Ri, a representation of the second svara in Indian classical music Russia Insider, a pro-Kremlin news and propaganda website Businesses and organizations Raffles Institution, a school in Singapore Refugees International, an international humanitarian organization Rehabilitation International, an international disability rights organization Rotary International, international organization of business and professional leaders focused on non-political and non-sectarian humanitarian service Royal Institution of Great Britain, an organisation devoted to scientific education and research Royal Institute of Painters in Water Colours, a society in the Federation of British Artists Chicago, Rock Island and Pacific Railroad (reporting mark RI) Tigerair Mandala (IATA airline designator RI) Italian Radicals, a political party in Italy Science, technology, and mathematics Ri (prefix symbol), a binary unit prefix symbol Referential integrity, a database concept Refractive index of an optical medium (in physics/optics) is a number that describes how light propagates through that medium Arterial resistivity index, a measure of pulsatile blood flow Ring Indicator, a signal in the RS232 serial communications standard Rhombicosahedron, a polyhedron, by Bowers acronym Residual income, a financial profitability measure of a company Reputation Institute, a research and insights company that analyzes the reputation of corporations and places Rapid intensification, a phenomenon in which the wind speed of a tropical cyclone increases dramatically in a short period of time Research infrastructure, national or international infrastructure open to scientists (e.g. CERN) Research institute, an establishment founded for doing research Other uses Ri (cuneiform), a cuneiform sign Ri (kana), a Romanization of the Japanese kana り and リ Ri, a unit of measurement in Japan and Korea related to the Chinese li Rock Island District, a commuter rail line on Chicago's Metra (abbreviated as RI on