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Definition of periodic - 8 dictionary results

pe⋅ri⋅od⋅ic

1  [peer-ee-od-ik]
Use periodic in a Sentence
–adjective
1. recurring at intervals of time: periodic revivals of an interest in handicrafts.
2. occurring or appearing at regular intervals: periodic visits of a mail steamer to an island.
3. repeated at irregular intervals; intermittent: periodic outbreaks of the disease.
4. Physics. recurring at equal intervals of time.
5. Mathematics. (of a function) having a graph that repeats after a fixed interval (period) of the independent variable.
6. Astronomy.
a. characterized by a series of successive circuits or revolutions, as the motion of a planet or satellite.
b. of or pertaining to a period, as of the revolution of a heavenly body.
7. pertaining to or characterized by rhetorical periods, or periodic sentences.
Origin:
1635–45; < L periodicus < Gk periodikós. See period, -ic

Related forms:
pe⋅ri⋅od⋅i⋅cal⋅ly, adverb

per⋅i⋅od⋅ic

2  [pur-ahy-od-ik]
–adjective Chemistry.
of or derived from a periodic acid.
Origin:
1830–40; per- + iodic
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
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pe·ri·od·ic   (pîr'ē-ŏd'ĭk)   
adj.  
  1. Having or marked by repeated cycles.
  2. Happening or appearing at regular intervals.
  3. Recurring or reappearing from time to time; intermittent.
  4. Characterized by periodic sentences.
pe'ri·od'i·cal·ly adv.
Synonyms: These adjectives all mean recurring or reappearing now and then. Something periodic occurs at regular or at least generally predictable intervals: periodic feelings of anxiety.
Sporadic implies scattered, irregular, unpredictable, or isolated instances: sporadic bombing raids.
Intermittent describes something that stops and starts at intervals: intermittent rain showers.
What is occasional happens at random and irregularly: occasional outbursts of temper.
Something fitful occurs in spells and often abruptly: fitful bursts of energy.

Usage Note: In technical use, periodic means "at regular or predictable intervals," as in the Periodic Table of the Elements. Often, however, periodic is used to mean "occasional, intermittent." This usage can be confusing for readers who are accustomed to the narrower sense of the word. Thus the writer who says Parker's losses at the track were not covered by his periodic wins invites the (most likely unintended) inference that Parker has a system that enables him to win at regular intervals. The ambiguity can be avoided here by using occasional instead.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Periodic

Per`i*od"ic\, a. [Pref. per- + iodic.] (Chem.) Pertaining to, derived from, or designating, the highest oxygen acid (HIO?) of iodine.

Periodic

Pe`ri*od"ic\, Periodical \Pe`ri*od"ic*al\, a. [L. periodicus, Gr. ?: cf. F. p['e]riodique.]

1. Of or pertaining to a period or periods, or to division by periods.

The periodicaltimes of all the satellites. --Sir J. Herschel.

2. Performed in a period, or regular revolution; proceeding in a series of successive circuits; as, the periodical motion of the planets round the sun.

3. Happening, by revolution, at a stated time; returning regularly, after a certain period of time; acting, happening, or appearing, at fixed intervals; recurring; as, periodical epidemics.

The periodic return of a plant's flowering. --Henslow.

To influence opinion through the periodical press. --Courthope.

4. (Rhet.) Of or pertaining to a period; constituting a complete sentence.

Periodic comet (Astron.), a comet that moves about the sun in an elliptic orbit; a comet that has been seen at two of its approaches to the sun.

Periodic function (Math.), a function whose values recur at fixed intervals as the variable uniformly increases. The trigonomertic functions, as sin x, tan x, etc., are periodic functions. Exponential functions are also periodic, having an imaginary period, and the elliptic functions have not only a real but an imaginary period, and are hence called doubly periodic.

Periodic law (Chem.), the generalization that the properties of the chemical elements are periodic functions of their atomic wieghts. "In other words, if the elements are grouped in the order of their atomic weights, it will be found that nearly the same properties recur periodically throughout the entire series." The following tabular arrangement of the atomic weights shows the regular recurrence of groups (under I., II., III., IV., etc.), each consisting of members of the same natural family. The gaps in the table indicate the probable existence of unknown elements. TABLE OF THE PERIODIC LAW OF THE CHEMICAL ELEMENTS (The vertical columns contain the periodic groups) Series1[ 2[ 3[ 4[ 5[ 6[ 7[ 8[ 9[ 10[ 11[ 12[ -------------------------------------------------------------- |I. II. III. IV. V. VI. VII. VIII. | RH4 RH3 RH3 RH |R2O RO R3O3 RO2 R2O5 RO3 R2O7 RO4 -------------------------------------------------------------- H 1 Li 7 Na 23 K 39 (Cu) 63 Rb 85.2 (Ag) (108) Cs 133 (-) (-) (Au) (197) (-) ---------------------------------------------------------------

Note: A similar relation had been enunciated in a crude way by Newlands; but the law in its effective form was developed and elaborated by Mendelejeff, whence it is sometimes called Mendelejeff's law. Important extensions of it were also made by L. Meyer. By this means Mendelejeff predicted with remarkable accuracy the hypothetical elements ekaboron, ekaluminium, and ekasilicon, afterwards discovered and named respectively scandium, gallium, and germanium.

Periodic star (Astron.), a variable star whose changes of brightness recur at fixed periods.

Periodic time of a heavenly body (Astron.), the time of a complete revolution of the body about the sun, or of a satellite about its primary.
Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
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Language Translation for : periodic
Spanish: periódico,
German: regelmäßig,
Japanese: 周期的な
More Translations »

periodic 
1642, from Fr. périodique (14c.), from L. periodicus, from periodus (see period). Periodical "magazine that publishes regularly" is first attested 1798. Periodic table in chemistry is from notion of the arrangement, in which similar properties recur at intervals in elements in the same area as you read down the rows of the table. This sense of the word is attested fromj 1872.
Online Etymology Dictionary, © 2001 Douglas Harper
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Main Entry: pe·ri·od·ic
Pronunciation: "pir-E-'äd-ik
Function: adjective
: occurring or recurring at regular intervals<periodic epidemics>
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
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periodic pe·ri·od·ic (pĭr'ē-ŏd'ĭk)
adj.

  1. Having or marked by repeated cycles.
  2. Recurring at regular intervals.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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