4H (disambiguation)

4H may refer to: * 4-H, a youth organization administered by the USDA * Curtiss JN-4H, an American biplane * 4H, a Washington, D.C. Metrobus route, in the United States * 4H-pyran * 4H-SiC, one of the polymorphs of silicon carbide * Hydrogen-4 (4H, or quadrium), an isotope of hydrogen * 4H, IATA code for United Airways, a Bangladeshi airline * 4H disease, an early name for AIDS since the syndrome seemed to affect heroin users, homosexuals, hemophiliacs, and Haitians * 4H, the production code for the 1975 Doctor Who serial Planet of Evil rdf:langString