Also found in: Dictionary, Thesaurus, Legal, Financial, Encyclopedia.
Related to apothecaries' weight: avoirdupois weight
1. heaviness; the degree to which a body is drawn toward the earth by gravity. (See also Tables of Weights and Measures in the Appendix.) Abbreviated wt.
2. in statistics, the process of assigning greater importance to some observations than to others, or a mathematical factor used to apply such a process.
apothecaries' weight see apothecaries' system.
atomic weight the sum of the masses of the constituents of an atom, expressed in atomic mass units (or daltons), in SI units (i.e., kilograms), or as a dimensionless ratio derived by comparing the mass to the mass of an atom of carbon-12, which is taken as 12.000. Abbreviated At wt.
avoirdupois weight see avoirdupois system.
equivalent weight the amount of substance that combines with or displaces 8.0 g of oxygen (or 1.008 g of hydrogen), usually expressed in grams; for acid/base reactions, one equivalent donates or receives a mole of protons and the equivalent weight is the ratio of the molecular weight to the number of protons involved in the reaction. For oxidation-reduction reactions, one equivalent donates or receives a mole of electrons and the equivalent weight is the ratio of the molecular weight to the number of electrons involved in the reaction.
gram molecular weight the molecular weight of a substance expressed in grams; one gram molecular weight of a molecular substance contains one mole of molecules. See also mole1.
low birth weight (LBW) see under infant.
molecular weight the weight of a molecule of a chemical compound as compared with the weight of an atom of carbon-12; it is equal to the sum of the weights of its constituent atoms and is dimensionless. Abbreviated Mol wt or MW. Although widely used, the term is not technically correct; relative molecular mass is preferable.
very low birth weight (VLBW) see under infant.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
A system of weights used in pharmacy and based on an ounce equal to 480 grains and a pound equal to 12 ounces. It has been largely replaced by measures of the metric system.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
apothecaries’ weightA non-SI (International System) measurement system defined by an Act of Parliament, based in 1824 on the troy pound and after 1855 on the avoirdupois pound, formerly used in clinical pharmacology.
Apothecaries’ weight units
• Grain (0.064 g);
• Scruple—20 grains (0.1280 g);
• Dram—3 scruples (0.3840 g);
• Ounce—8 drams (30.720 g);
— Troy pound—12 ounces (368.64 g);
— Avoirdupois pound—16 ounces (454 g).
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
a·poth·e·car·ies' weight(ă-poth'ĕ-kar-ēz wāt)
A system of weights based on the weight of a grain of wheat; superseded by the metric system (based on grams). One grain is the equivalent of 64.8 mg. One scruple contains 20 grains; 1 dram contains 60 grains; 1 apothecary ounce contains 8 drams (480 grains); 1 apothecary pound contains 12 ounces (5760 grains).
Medical Dictionary for the Health Professions and Nursing © Farlex 2012