depression

noun8

1. •
   The act of lowering or pressing something down.

   • Depression of the lever starts the machine.
2. •
   a mental illness that makes someone feel low for a long time, without hope or joy in daily life

   • I used to suffer from depression, but now I'm mostly content with my life.
3. •
   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.

   • […] your illness reflects the textbook description of bipolar disorder (euphoric, grandiose, manic highs followed by deep depressions,[…] — 2011
4. •
   A period of major economic contraction.
5. •
   Four consecutive quarters of negative, real GDP growth (for example, this operational definition is used by the US NBER and many other writers).

   • The Great Depression was the worst financial event in US history.
6. •
   An area of lowered air pressure that generally brings moist weather, sometimes promoting hurricanes and tornadoes.
7. •
   An area that is lower in topography than its surroundings.
8. •
   A lowering, in particular a reduction in a particular biological variable or the function of an organ, in contrast to elevation.