American Meteorological Society - Glossary of Meteorology

depression

  1. In general, a point or limited area of locally lower elevation in a particular surface.
  2. In meteorology, an area of low pressure; a low or trough.
    This is usually applied to a certain stage in the development of a tropical cyclone, to migratory lows and troughs, and to upper-level lows and troughs that are only weakly developed. This use of the term is most common in the European literature.
    See V-shaped depression.
  3. Same as depression angle.
  4. See wet-bulb depression, dewpoint spread.