Noun
(biology) Initialism of extracellular volume, the volume of fluid, etc., in an organism that is outside the organism's cells.
(physiology) Initialism of effective circulating volume, the volume of arterial blood effectively perfusing tissue.
(medicine) Initialism of external cephalic version, a method of manually repositioning a foetus to avoid a breech birth.
Source: en.wiktionary.orgOnly one has been produced. citation M1113 Expanded Capacity Vehicle (ECV) Under contract to the US Army, AM General developed the M1113 Expanded Capacity Vehicle (ECV). Source: Internet