depression

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act of depressing.
• noun The condition of being depressed.
• noun An area that is sunk below its surroundings; a hollow.
• noun The condition of feeling sad or despondent.
• noun A mood disorder characterized usually by anhedonia, extreme sadness, poor concentration, sleep problems, loss of appetite, and feelings of guilt, helplessness, and hopelessness.
• noun A lowering or reduction, as.
• noun A reduction in physiological vigor or activity.
• noun A lowering in amount, degree, or position.
• noun A period of drastic economic decline, characterized by decreasing aggregate output, falling prices, and rising unemployment.
• noun A period of widespread poverty and high unemployment.
• noun Meteorology A region of low barometric pressure.
• noun The angular distance below the horizontal plane through the point of observation.
• noun Astronomy The angular distance of a celestial body below the horizon.

from The Century Dictionary.

• noun The difference between the low barometric pressure and the normal pressure for that locality; the departure of the pressure.
• noun The act of pressing down, or the state of being pressed down. Specifically
• noun In astronomy:
• noun In gunnery, the lowering of the muzzle of a gun, corresponding to the raising of the breech.
• noun In surgery, a kind of couching.
• noun In music, the lowering or flatting of a tone: denoted in printed music by a ♭, or, after a ♯, by a ♯.
• noun A hollow; a sinking or falling in of a surface; a forcing inward: as, roughness consisting in little protuberances and depressions; the depression of the skull.
• noun Figuratively, the act of lowering or abasing: as, the depression of pride.
• noun A sinking of the spirits; dejection; a state of sadness; want of courage or animation: as, depression of the mind.
• noun A low state of strength; physical exhaustion.
• noun A state of dullness or inactivity: as, depression of trade; commercial depression.
• noun Humiliation, fall.
• noun Melancholy, despondency.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of depressing.
• noun The state of being depressed; a sinking.
• noun A falling in of the surface; a sinking below its true place; a cavity or hollow.
• noun Humiliation; abasement, as of pride.
• noun Dejection; despondency; lowness.
• noun Diminution, as of trade, etc.; inactivity; dullness.
• noun (Astron.) The angular distance of a celestial object below the horizon.
• noun (Math.) The operation of reducing to a lower degree; -- said of equations.
• noun (Surg.) A method of operating for cataract; couching. See Couch, v. t., 8.
• noun (Geod.) one which a descending line makes with a horizontal plane.
• noun (Meteor.) the number of degrees that the dew-point is lower than the actual temperature of the atmosphere.
• noun its apparent sinking, as the spectator goes toward the equator.
• noun (Astron.) Same as Dip of the horizon, under Dip.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun geography an area that is lower in topography than its surroundings
• noun psychology in psychotherapy and psychiatry, a state of mind producing serious, long-term lowering of enjoyment of life or inability to visualize a happy future
• noun psychology in psychotherapy and psychiatry, a period of unhappiness or low morale which lasts longer than several weeks and may include ideation of self-inflicted injury or suicide
• noun meteorology an area of lowered air pressure that generally brings moist weather, sometimes promoting hurricanes and tornadoes
• noun economics a period of major economic contraction;
• noun economics, US Four consecutive quarters of negative, real GDP growth. See NBER.
• noun biology, physiology a lowering, in particular a reduction in a particular biological variable or the function of an organ, in contrast to elevation

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a period during the 1930s when there was a worldwide economic depression and mass unemployment