Orn

Orn or ORN may refer to:


 * Orn (name), a given name and surname
 * Orn, the second book in Piers Anthony's trilogy Of Man and Manta
 * Offshoring Research Network, an international network researching the offshoring of business processes and services
 * Olfactory receptor neuron, a type of cell in the nasal mucosa that transduces the presence of odorant molecules into a neural signal
 * Olympic route network, a network of dedicated roads linking venues and other key sites in the host city during Olympic games
 * Oran Es Sénia Airport (IATA code), an international airport in Es Sénia, Algeria
 * Ornithine, an amino acid that plays a role in the urea cycle
 * Osteoradionecrosis, a complication of radiation therapy where a section of bone dies