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.