(geography) an area that is lower in topography than its surroundings
(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
(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
(meteorology) an area of lowered air pressure that generally brings moist weather, sometimes promoting hurricanes and tornadoes
(economics) a period of major economic contraction;
(economics, US) Four consecutive quarters of negative, real GDP growth. See NBER.
The Great Depression was an event in US history.
(biology, physiology) a lowering, in particular a reduction in a particular biological variable or the function of an organ, in contrast to elevation