CAS RN

number

(num'ber) [L. numerus, number] 1. A total of units. 2. A symbol graphically representing an arithmetical sum.

atomic mass number

A number equal to the sum of all the neutrons and the protons in an atom's nucleus. See: mass number

atomic number

Z The number of negatively charged electrons in an uncharged atom, or the number of protons in the nucleus. This number determines the position of elements in the periodic table of elements. It is used to describe isotopes of an element, each of which has a different mass number but the same atomic number.

Avogadro number

See: Avogadro, Amedeo

CAS number

Abbreviation: CAS RN, CAS #
An internationally recognized identifier for each chemical published by the Chemical Abstract Service (CAS). The CAS maintains a database for all known chemicals, including basic properties, toxicity, flammability, and radioactivity.

Drug Enforcement Administration number

See: Drug Enforcement Administration number

hardness number

A number on a calibrated scale indicating the relative hardness as determined by a particular system of testing, e.g., Knoop, Mohs, Rockwell, Vickers hardness tests. A steel ball or diamond point is applied with a known variable load for a determined period of time to produce an indent whose depth or diameter can be measured.

lot number

An identifier assigned to a batch of medications. It facilitates drug manufacturing inventory control and tracing adverse incidents in a batch of contaminated medications.

low density lipoprotein particle number

Low density lipoprotein particle concentration.

mass number

The mass of the atom of a specific isotope relative to the mass of hydrogen. In general, this number is equal to the total of the protons and neutrons in the atomic nucleus of that specific isotope.

OMIM number

MIM #.

saponification number

In analysis of fats, the number of milligrams of potassium hydroxide needed to saponify 1 g of oil or fat.

Unique Physician Identification Number

See: Unique Physician Identification Number