British thermal unit

unit (u´nit)

1. a single thing.

2. a quantity assumed as a standard of measurement. Symbol U.

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Angström unit  angstrom.

atomic mass unit  (u) (amu) the unit mass equal to 112 the mass of the nuclide of carbon-12. Called also dalton.

Bethesda unit  a measure of the level of inhibitor to coagulation factor VIII; equal to the amount of inhibitor in patient plasma that will inactivate 50 per cent of factor VIII in an equal volume of normal plasma following a 2-hour incubation period.

Bodansky unit  the quantity of alkaline phosphatase that liberates 1 mg of phosphate ion from glycerol 2-phosphate in 1 hour under standard conditions.

British thermal unit  (BTU) the amount of heat necessary to raise the temperature of one pound of water one degree Fahrenheit, usually from 39°F to 40°F.

CGS unit  any unit in the centimeter-gram-second system.

CH50 unit  the amount of complement that will lyse 50 per cent of a standard preparation of sheep red blood cells coated with antisheep erythrocyte antibody.

coronary care unit  a specially designed and equipped hospital area containing a small number of private rooms, with all facilities necessary for constant observation and possible emergency treatment of patients with severe heart disease.

intensive care unit  a hospital unit in which are concentrated special equipment and skilled personnel for the care of seriously ill patients requiring immediate and continuous attention; abbreviated ICU.

International unit  (IU) a unit of biological material, as of enzymes, hormones, vitamins, etc., established by the International Conference for the Unification of Formulas.

motor unit  the unit of motor activity formed by a motor nerve cell and its many innervated muscle fibers.

SI unit  any of the units of the Système International d'Unités (International System of Units) adopted in 1960 at the Eleventh General Conference of Weights and Measures.

Somogyi unit  that amount of amylase which will liberate reducing equivalents equal to 1 mg of glucose per 30 minutes under defined conditions.

Svedberg unit  (S) a unit equal to 10−13 second used for expressing sedimentation coefficients of macromolecules.

terminal respiratory unit  the anatomical and functional unit of the lung, including a respiratory bronchiole, alveolar ducts and sacs, and alveoli.

toxic unit , toxin unit the smallest dose of a toxin which will kill a guinea pig weighing about 250 gm in three to four days.

USP unit  one used in the United States Pharmacopeia in expressing potency of drugs and other preparations.

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British thermal unit

n. Abbr. Btu

1. The quantity of heat required to raise the temperature of one pound of water from 60° to 61°F at a constant pressure of one atmosphere.

2. The quantity of heat equal to ¹/₁₈₀ of the heat required to raise the temperature of one pound of water from 32° to 212°F at a constant pressure of one atmosphere.

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British thermal unit (BTU),

a unit of heat energy. The amount of thermal energy that must be absorbed by 1 lb of water to raise its temperature by 1° at 39.2° F. It is also equivalent to 1055 joules or 252 calories.

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British thermal unit

BTU, a unit of heat being the amount necessary to raise the temperature of 1 pound of water from 39 to 40°F, generally considered the equivalent of 252 calories.

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British Thermal Unit

A unit of energy–equal to 252 calories or 1055 Joules needed to raise one pound of water by one degree Fahrenheit