The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
in music, a structural unit that expresses a complete or relatively complete musical idea. Usually, a period consists of two parts (phrases), each made up of four or eight measures that differ in their cadences (a half cadence in the first phrase and a perfect cadence in the second).
(postroenie), in music, a term that is applicable to any section of a musical form that is structurally distinct from adjacent sections. Usually the term is applied to sections intervening between the main elements of a musical form—for example, sections larger than a phrase but smaller than a sentence. Often, a period is designated by the number of measures it includes (two-measure, four-measure and seven-measure periods, for example). The point of demarcation, or boundary between periods, is called a caesura. Usually the larger the periods, the more important is the caesura dividing them.
a punctuation mark that indicates the end of a declarative sentence. When used in such abbreviations as “i.e., ” the period is not a punctuation mark.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
The average time interval for a variable star to complete a cycle of its variations.
A family of elements with consecutive atomic numbers in the periodic table and with closely related properties; for example, chromium through copper.
A unit of geologic time constituting a subdivision of an era; the fundamental unit of the standard geologic time scale.
A number T such that ƒ(x + T) = ƒ(x) for all x, where ƒ(x) is a specified function of a real or complex variable.
The period of an element a of a group G is the smallest positive integer n such that a n is the identity element; if there is no such integer, a is said to be of infinite period.
The time required for exponentially rising or falling neutron flux in a nuclear reactor to change by a factor of e (2.71828).
The duration of a single repetition of a cyclic phenomenon.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
1. a nontechnical name for an occurrence of menstruation
2. Geology a unit of geological time during which a system of rocks is formed
3. a division of time, esp of the academic day
4. Physics Maths
a. the time taken to complete one cycle of a regularly recurring phenomenon; the reciprocal of frequency.
b. an interval in which the values of a periodic function follow a certain pattern that is duplicated over successive intervals
a. the time required by a body to make one complete rotation on its axis
b. the time interval between two successive maxima or minima of light variation of a variable star
6. Chem one of the horizontal rows of elements in the periodic table. Each period starts with an alkali metal and ends with a rare gas
7. a complete sentence, esp a complex one with several clauses
8. Music a passage or division of a piece of music, usually consisting of two or more contrasting or complementary musical phrases and ending on a cadence
9. (in classical prosody) a unit consisting of two or more cola
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005