Columbia Encyclopedia

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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 ...

birth

(Encyclopedia)birth or labor, delivery of the fetus by the viviparous mammal. Birth is also known as parturition. Human birth normally occurs about 280 days after onset of the last menstrual period before conceptio...

multiple birth

(Encyclopedia)multiple birth, bringing forth of more than one offspring at birth. Although many smaller mammals bear several young at a time, multiple births are relatively uncommon in humans and other primates. Tw...

birth defects

(Encyclopedia)birth defects, abnormalities in physical or mental structure or function that are present at birth. They range from minor to seriously deforming or life-threatening. A major defect of some type occurs...

birth rate

(Encyclopedia)birth rate: see vital statistics. ...

gun control

(Encyclopedia)gun control, government limitation of the purchase and ownership of firearms. The availability of guns is controlled by nations and localities throughout the world. In the United States the “right o...

control surface

(Encyclopedia)control surface: see airfoil.

control systems

(Encyclopedia)control systems, combinations of components (electrical, mechanical, thermal, or hydraulic) that act together to maintain actual system performance close to a desired set of performance specifications...

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...

numerical control

(Encyclopedia)numerical control: see computer-aided manufacturing. ...