ExpertGlossary terms starting with H

1,452 terms

  1. Heaviside layer Synonym E region.
  2. Heavy Freezing Spray An accumulation of freezing water droplets on a vessel at a rate of 2 cm per hour or greater caused by some appropriate combination of cold water, wind…
  3. Heavy Freezing Spray Warning A warning that may be issued within the Offshore Waters Forecast, the Coastal Waters Forecast, the Nearshore Marine Forecast, and the Open Lake Forecast…
  4. Heavy metals Metallic elements with high atomic weights (e.g., mercury, chromium, cadmium, arsenic, and lead); can damage living things at low concentrations and tend…
  5. Heavy Replicas (HREPS) Decoys, which by virtue of shape, size, and mass, closely approximate an RVs signature. HREPS have significant off- load penalty.
  6. Heavy Snow This generally means... snowfall accumulating to 4" or more in depth in 12 hours or less; or snowfall accumulating to 6" or more in depth in 24 hours or…
  7. Heavy Snow Warning Issued by the National Weather Service when snowfall of 6 inches (15 cm) or more in 12 hours or 8 inches (20 cm) or more in 24 hours is imminent or…
  8. Heavy Surf Advisory An advisory issued by the National Weather Service for fast moving deep water waves which can result in big breaking waves in shallow water (the surf…
  9. HECM (Reverse Mortgage) The reverse mortgage is used by senior homeowners age 62 and older to convert the equity in their home into monthly streams of income and/or a line of…
  10. Hectare An area equal to 2.47 acres. There are 100 hectares in 1 square kilometer.
  11. Hectopascal A unit of pressure equal to a millibar (1 hPa = 1 mb). Abbreviated hPa.
  12. Hedge fund Hedge funds are private investment partnerships open to institutions and wealthy individual investors.
  13. Hedger Hedgers in the futures market try to offset potential price changes in the spot market by buying or selling a futures contract.
  14. Hedging Hedging is an investment technique designed to offset a potential loss on one investment by purchasing a second investment that you expect to perform in…
  15. HEDI OBSOLETE. See High Endoatmospheric Defense Interceptor.
  16. Hedonic – (modeling approach) The hedonic method is a regression technique used to estimate the prices of qualities or models that are not available on the market in particular…
  17. Hedonic statistical framework A method of assessing the impact of various structural (number of bedrooms, bathrooms, square footage, age, etc.
  18. HEDR High Endoatmospheric Defense Radar.
  19. HEDS High Endoatmospheric Defense System.
  20. Hedyotis diffusa An herb used in traditional Chinese medicine to treat certain medical problems.
  21. Heel of Dam The junction of the upstream face of a concrete gravity dam or arch dam with the ground surface.
  22. HEI High Endoatmospheric Interceptor.
  23. Height In meteorology, usually a reference to Geopotential Height; roughly the height above sea level of a pressure level.
  24. height gain For a given propagation mode of an electromagnetic wave, the ratio of the field strength at a specified height to the field strength at the surface of the…
  25. Height of dam. See hydraulic height or structural height.
  26. Heinrich Events periods of increased discharge of icebergs from the margin of ice sheets into the North Atlantic Ocean during the last glacial.
  27. HEL High Energy Laser.
  28. Helical Spiral.
  29. helical antenna An antenna that has the form of a helix. Note: When the helix circumference is much smaller than one wavelength, the antenna radiates at right angles to…
  30. helical computed tomography (HEH-lih-kul kum-PYOO-ted toh-MAH-gruh-fee) A detailed picture of areas inside the body.
  31. helical scan A method of recording video information diagonally on a tape, used in home and professional video cassette recorders (VCRs).
  32. Helical scan recording The recording format in which a slow moving tape is helically wrapped 180° around a rapidly rotating drum with a small embedded record head.
  33. Helicity A property of a moving fluid which represents the potential for helical flow (i.e. flow which follows the pattern of a corkscrew) to evolve.
  34. Helicobacter pylori (HEEL-ih-koh-BAK-ter py-LOR-ee) A type of bacterium that causes inflammation and ulcers in the stomach or small intestine.
  35. Heliocentric A model of the universe published by Nicolaus Copernicus, and proven by Galileo (who viewed the phases of venus with his telescope), which puts our sun at…
  36. Heliochemical Process The utilization of solar energy through photosynthesis.
  37. Heliodon A device used to simulate the angle of the sun for assessing shading potentials of building structures or landscape features.
  38. Heliosphere A huge magnetic bubble containing the solar wind and the entire solar magnetic field.
  39. Heliostat A device that tracks the movement of the sun; used to orient solar concentrating systems.
  40. Heliothermal Any process that uses solar radiation to produce useful heat.
  41. Heliothermic Site planning that accounts for natural solar heating and cooling processes and their relationship to building shape, orientation, and siting.
  42. Heliothermometer An instrument for measuring solar radiation.
  43. Heliotropic Any device (or plant) that follows the sun's apparent movement across the sky.
  44. helix A structure with a spiral shape. The normal state of double-stranded DNA is in the form of a double helix.
  45. HELKS High Energy Laser Kill System.
  46. hellgramite The larvae of the dobsonfly.
  47. HELLO High Energy Laser Light Opportunity.
  48. helminth A class of parasitic worms, especially those which are internal parasites of man and animals.
  49. HELP Homebuyer Education Learning Program; an educational program from the FHA that counsels people about the home buying process; HELP covers topics like…
  50. Help America Vote Act (HAVA) Congress passed HAVA to address voting problems encountered in the 2000 presidential election.
  51. helper cell T cells that assist in stimulating B and T lymphocyte s to develop into antibody-producing plasma cells and killer T cells, respectively.
  52. helper plasmid A plasmid that provides a function or functions to another plasmid in the same cell.
  53. helper T cell A type of white blood cell that helps stimulate immune system reactions. Helper T cells help activate cytotoxic T cells and macrophages by secreting…
  54. helper T lymphocyte See: helper cell.
  55. helper virus A virus that provides a function or functions to another virus in the same cell.
  56. HELSTF High Energy Laser Systems Test Facility.
  57. HELWS High Energy Laser Weapon System.
  58. hemagglutinin-neuraminidase A protein found in the outer coat of paramyxoviruses. This protein helps virus particles bind to cells, making infection easier.
  59. hemangiopericytoma (heh-MAN-jee-oh-PAYR-ih-sy-TOH-muh) A type of cancer involving blood vessels and soft tissue.
  60. hemangiosarcoma A type of cancer that begins in the cells that line blood vessels.
  61. Hematocrit The amount of blood consisting of red blood cells, measured as a percentage.
  62. hematogenous (HEE-muh-TAH-jeh-nus) Originating in the blood or spread through the bloodstream.
  63. Hematologic Having to do with the blood.
  64. hematologic cancer (HEE-muh-tuh-LAH-jik KAN-ser) A cancer of the blood or bone marrow, such as leukemia or lymphoma.
  65. Hematological Oncologist A medical doctor who specializes in diagnosing and treating malignancies, or cancers, of the blood and blood- forming tissues.
  66. Hematologist (HEE-muh-TAH-loh-jist) A doctor who specializes in treating blood disorders.
  67. hematoma (HEE-muh-TOH-muh) A pool of clotted or partially clotted blood in an organ, tissue, or body space, usually caused by a broken blood vessel.
  68. Hematopoiesis (hee-MA-toh-poy-EE-sus) The formation of new blood cells.
  69. Hematopoietic cell transplantation The transplantation of hematopoietic stem cells with blood-forming potential. Hematopoietic stem cells provide rapid and sustained reconstitution of blood…
  70. hematopoietic growth factor (hee-MA-toh-poy-EH-tik ...) A group of proteins that causes blood cells to grow and mature.
  71. Hematopoietic stem cell An unspecialized precursor cell that will develop into a mature blood cell. See also cell
  72. Hematopoietic stem cell (HSC) A stem cell from which all red and white blood cells evolve.
  73. Hematopoietic stem cells The precursors of mature blood cells that are defined by their ability to replace the bone marrow system following its obliteration (for example, by…
  74. hematopoietic tissue (hee-MA-toh-poy-EH-tik TIH-shoo) Tissue in which new blood cells are formed.
  75. hematoporphyrin derivative (HEE-muh-toh-POR-fih-rin deh-RIH-vuh-tiv) A drug used in photodynamic therapy that is absorbed by tumor cells.
  76. hematuria (HEE-muh-TOOR-ee-uh) Blood in the urine.
  77. heme (heem) The part of certain molecules that contains iron. The heme part of hemoglobin is the substance inside red blood cells that binds to oxygen in the lungs…
  78. hemicellulase An enzyme that catalyses the degradation of hemicellulose.
  79. hemicellulose Any cellulose-like carbohydrate, but excluding cellulose itself. Together with pectin and lignin, hemicelluloses form the cell wall matrix.
  80. hemihypertrophy (HEM-ee-hy-PER-troh-fee) A condition in which one side of the body or a part of one side is larger than the other.
  81. hemilaryngectomy (HEM-ee-LA-rin-JEK-toh-mee) An operation to remove one side of the larynx (voicebox).
  82. Hemispherical Bowl Technology A solar energy concentrating technology that uses a linear receiver that tracks the focal area of a reflector or array of reflectors.
  83. Hemizygous The condition in which genes are present only once in the genotype and not in pairs.
  84. hemochromatosis (HEE-moh-kroh-muh-TOH-sis) A condition in which the body absorbs more iron from food than it needs.
  85. Hemodialysis The most common form of treatment for end stage renal failure. Surgery is required to join one artery to a vein to form a larger vein called a fistula or…
  86. hemoglobin (HEE-moh-GLOH-bin) The substance inside red blood cells that binds to oxygen in the lungs and carries it to the tissues.
  87. hemolymph See: haemolymph.
  88. Hemolysis Destruction of red blood cells. Malaria causes hemolysis when the parasites rupture the red blood cells in which they have grown.
  89. hemophagocytic lymphohistiocytosis (HEE-moh-FAG-oh-SIT-ik LIM-foh-HIS-tee-oh-sy-TOH-sis) A rare disorder in which histiocytes and lymphocytes (types of white blood cells) build up in organs…
  90. hemophilia Group of hereditary disorders in which affected individuals fail to make enough of certain proteins needed to form blood clots.
  91. hemoptysis (hee-MOP-tih-sis) Coughing or spitting up blood from the respiratory tract.
  92. hemorrhage In medicine, loss of blood from damaged blood vessels. A hemorrhage may be internal or external, and usually involves a lot of bleeding in a short time.
  93. hemorrhoid (HEH-muh-ROYD) An enlarged or swollen blood vessel, usually located near the anus or the rectum.
  94. HEMP High Altitude Electromagnetic Pulse. 126
  95. HEMTT Heavy Expanded Mobility Tactical Truck (US Army prime mover).
  96. Hen House Soviet area defense radar used as a component of the Moscow ABM system that provides VHF coverage of space to monitor orbiting satellites and early…
  97. Henry Hub A location near the coastal town of Egan, LA and the Texas border where more than a dozen major natural gas pipelines converge and exchange gas.
  98. HEO See High Earth Orbit.
  99. HEPA filter Abbreviation for high efficiency particulate air filter. A filter capable of excluding particles larger than 0.3ìm.
  100. heparin (HEH-puh-rin) A substance that slows the formation of blood clots. Heparin is made by the liver, lungs, and other tissues in the body and can also made in…