Depression
From Glossary of Meteorology
depression
- In general, a point or limited area of locally lower elevation in a particular surface.
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.
Same as depression angle.