Organizations

• Halifax Port Authority
  Halifax Port Authority
  The Halifax Port Authority is a port authority operating as a not-for-profit Crown corporation of the Government of Canada. HPA has responsibility for all federally-owned waterfront properties on Halifax Harbour in Nova Scotia's Halifax Regional Municipality.The HPA was created on March 1, 1999...
  
  , a port authority in Canada
• Hamburg Port Authority, the port authority for the Port of Hamburg, Germany
• Health Protection Agency
  Health Protection Agency
  The Health Protection Agency, or, in Welsh, Yr Asiantaeth Diogelu Iechyd is a statutory corporation. It is an independent UK organisation that was set up by the government in 2003 to protect the public from threats to their health from infectious diseases and environmental hazards...
  
  , a health organization in the United Kingdom
• Hurlingham Polo Association
  Hurlingham Polo Association
  The Hurlingham Polo Association is the governing body for polo in the United Kingdom and Republic of Ireland. The Federation of International Polo produces the International Rules of Polo through a cooperative agreement with the Hurlingham Polo Association, the Asociación Argentina de Polo , plus...
  
  , the governing body for polo in the UK
• Hawaii Paragliding Association, a local chapter of the United States Hang Gliding and Paragliding Association on O'ahu in Hawaii, USA

Science

• Hectopascal (hPa), a unit of pressure equivalent to about 1/1000 of 1 atmosphere
• Hypothalamic-pituitary-adrenal axis
  Hypothalamic-pituitary-adrenal axis
  The hypothalamic-pituitary-adrenal axis , also known as thelimbic-hypothalamic-pituitary-adrenal axis and, occasionally, as the hypothalamic-pituitary-adrenal-gonadotropic axis, is a complex set of direct influences and feedback interactions among the hypothalamus, the pituitary gland ,...
  
   in physiology, regulation of hormone levels and maintaining homeostasis
• Human physical appearance
  Human physical appearance
  Human physical appearance refers to the outward phenotype or look of human beings. There are infinite variations in human phenotypes, though society reduces the variability to distinct categories...
  
  , in anthropology
• Human platelet antigens, in clinical medicine, blood transfusion, alloantigens
• Heteropoly acid
  Heteropoly acid
  A heteropoly acid is a class of acid made up of a particular combination of hydrogen and oxygen with certain metals and non-metals. This type of acid is frequently used as a re-usable acid catalyst in chemical reactions....
  
  , often used as an acidic catalyst

Technology

• High-Performance Addressing
  High-Performance Addressing
  High-Performance Addressing was developed by Hitachi and is an LCD Passive-matrix display technology commonly found on low-end portable computers...
  
  , a passive-matrix LCD display technology
• High Power Amplifier, part of the transceiver in two-way satellite dishes
• Host Protected Area
  Host Protected Area
  The host protected area, sometimes referred to as hidden protected area, is an area of a hard drive that is not normally visible to an operating system .- History :HPA was first introduced in the ATA-4 standard cxv .-How it works:...
  
  , a reserved and hidden area on computer data storage
• Human-powered aircraft
  Human-powered aircraft
  A human-powered aircraft is an aircraft powered by direct human energy and the force of gravity; the thrust provided by the human may be the only source; however, a hang glider that is partially powered by pilot power is a human-powered aircraft where the flight path can be enhanced more than if...
  
  
• High Pressure Air, gas propulsion in paintball guns