HPA
(HPA) şu anlamlara gelebilir: Hipotalamus-hipofiz-adrenal aks (HPA aksı) ya da Limbik-Hipotalamus-hipofiz-adrenal aks (LHPA), kompleks geribildirim mekanizmalarına sahip nöroendokrin bir yolak Hectopascal (hPa), 1 atmosfer basıncının yaklaşık 1/1000'ine eşit ölçü birimi, bir hectopascal bir milibara eşittir Hans Peter Anvin veya kısaca "hpa", İsveçli bilgisayar programcısı
<!-- Home Price Appreciation, the change in value of a single-family home, calculated using the United States Office of Federal Housing Enterprise Oversight's House Price Index Halifax Port Authority, a port authority operating as a not-for-profit Crown corporation of the Government of Canada
Hamburg Port Authority, the port authority for the Port of Hamburg, Germany
Health Protection Agency, an independent health organization in the United Kingdom responsible for protecting the population from hazards such as radiation, chemicals, poisons and infectious diseases
Hurlingham Polo Association, the governing body for polo in the UK Hectopascal (hPa), a unit of pressure equivalent to about 1/1000 of 1 atmosphere. Hypothalamic-pituitary-adrenal axis (physiology), how the hypothalamus, pituitary and adrenal glands work together to regulate hormone levels and maintain homeostasis
Human physical appearance (anthropology)
Human platelet antigens (Clinical Medicine, Blood transfusion, alloantigens)
Heteropoly acid, often used as an acidic catalyst High Performance Addressing, an LCD display technology, a passive-matrix display technology which provides better response rates and contrast than traditional LCD displays. They aren't as crisp or fast as active-matrix (TFT) displays, however they're a lot cheaper to produce.