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mastectomy

(Encyclopedia)mastectomy măstĕkˈtəmē [key], surgical removal of breast tissue, usually done as treatment for breast cancer. There are many types of mastectomy. In general, the farther the cancer has spread, th...

rheumatic fever

(Encyclopedia)rheumatic fever ro͞omătˈĭk [key], systemic inflammatory disease, extremely variable in its manifestation, severity, duration, and aftereffects. It is frequently followed by serious heart disease, ...

governor, device

(Encyclopedia)governor, automatic device used to regulate and control such variables as speed or pressure in the functioning of an engine or other machine. A governor may be an electric, hydraulic, or mechanical de...

United States Air Force Academy

(Encyclopedia)United States Air Force Academy, at Colorado Springs, Colo.; for training young men and women to be officers in the U.S. air force; authorized in 1954 by Congress. Temporary quarters were opened at th...

Preemption Act

(Encyclopedia)Preemption Act, statute passed (1841) by the U.S. Congress in response to the demands of the Western states that squatters be allowed to preempt lands. Pioneers often settled on public lands before th...

flextime

(Encyclopedia)flextime, system of assigning hours for work that permits employees to choose, within specified limits, the hours that they will be at their place of employment. In many companies, there is a “core ...

innate ideas

(Encyclopedia)innate ideas, in philosophy, concepts present in the mind at birth as opposed to concepts arrived at through experience. The theory has been advanced at various times in the history of philosophy to s...

insomnia

(Encyclopedia)insomnia, abnormal wakefulness or inability to sleep. The condition may result from illness or physical discomfort, or it may be caused by stimulants such as coffee or drugs. However, frequently some ...

Haggai

(Encyclopedia)Haggai hăgˈāī [key], prophetic book of the Bible. Dated 520 b.c., it is a collection of five oracles addressed to Jews, newly returned from the Babylonian exile. The prophet summons the people to ...

biodiesel

(Encyclopedia)biodiesel, fuel made from natural, renewable sources, such as new and used vegetable oils and animal fats, for use in a diesel engine. Biodiesel has physical properties very similar to petroleum-deriv...