High"-pres`sure (?; 135), a. 1. Having or involving a pressure greatly exceeding that of the atmosphere; -- said of steam, air, water, etc., and of steam, air, or hydraulic engines, water wheels, etc.

2. Fig.: Urgent; intense; as, a high- pressure business or social life.

High-pressure engine, an engine in which steam at high pressure is used. It may be either a condensing or a noncondensing engine. Formerly the term was used only of the latter. See Steam engine.