RH

RH, Rh, rH, or rh may refer to:

Companies

 * Red Hat, an American software company
 * Republic Express Airlines (IATA designator), a cargo airline in Indonesia
 * RH (company), an American furniture chain formerly known as Restoration Hardware

Science and technology

 * Relative humidity, the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature
 * Releasing hormone
 * Rh blood group system (Rhesus factor), a classification to describe blood types in humans
 * Rhodium, symbol Rh, a chemical element
 * RH, the Rydberg constant for hydrogen
 * Riemann hypothesis, an important unsolved problem in mathematics
 * Adobe RoboHelp, an Adobe software

Places

 * RH postcode area, in the UK
 * Republika Hrvatska, an official name of Croatia in Croatian

Other uses

 * Rh (digraph)
 * The Right Honourable, an honorific preceding a name in the UK
 * Radical honesty, the practice of always being completely honest and refraining from telling even white lies