Meaning

1. A state of mind producing serious, long-term lowering of enjoyment of life or inability to visualize a happy future.
2. A period of low morale or unhappiness (a period of experiencing the above-mentioned state of mind) which lasts longer than several weeks and may include ideation of self-inflicted injury or suicide.
3. An area that is lower in topography than its surroundings.
4. An area of lowered air pressure that generally brings moist weather, sometimes promoting hurricanes and tornadoes.
5. A period of major economic contraction.
6. Four consecutive quarters of negative, real GDP growth. See NBER.
7. The act of lowering or pressing something down.
8. A lowering, in particular a reduction in a particular biological variable or the function of an organ, in contrast to elevation.