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birth control

(Encyclopedia)birth control, practice of contraception for the purpose of limiting reproduction. Although contraceptive techniques had been known in ancient Egypt, Greece, and Rome, the modern movement for birth ...

rent control

(Encyclopedia)rent control, in economics and law, government regulation of rent to prevent unreasonable or excessive increases. In the United States, the federal government imposed rent control (and other price con...

white-slave traffic

(Encyclopedia)white-slave traffic: see prostitution. ...

air forces

(Encyclopedia)air forces, those portions of a nation's military organization employing heavier-than-air aircraft for reconnaissance, support of ground troops, aerial combat, and bombing of enemy lines of communicat...

Waves

(Encyclopedia)Waves (Women Appointed for Voluntary Emergency Service), U.S. navy organization, created (1942) in World War II to release male naval personnel for sea duty. The organization was commanded until 1946 ...

compressed air

(Encyclopedia)compressed air, air whose volume has been decreased by the application of pressure. Air is compressed by various devices, including the simple hand pump and the reciprocating, rotary, centrifugal, and...

air transportation

(Encyclopedia)air transportation: see aviation. ...

liquid air

(Encyclopedia)liquid air, ordinary air that has been liquefied by compression and cooling to extremely low temperatures (see liquefaction). Its commercial preparation involves purification by washing to remove solu...

lock, air

(Encyclopedia)lock, air: see air lock.

plein-air

(Encyclopedia)plein-air plān-ârˈ, Fr. plĕn-ĕrˈ [key] [Fr.,=open-air], term used for paintings or drawings made directly from nature and infused with a feeling of the open air. Painting outdoors is a relativel...