from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. An interval of time characterized by the occurrence of a certain condition, event, or phenomenon: a period of economic prosperity.
  • n. An interval of time characterized by the prevalence of a specified culture, ideology, or technology: artifacts of the pre-Columbian period.
  • n. An interval regarded as a distinct evolutionary or developmental phase: Picasso's early career is divided into his blue period and rose period.
  • n. Geology A unit of time, longer than an epoch and shorter than an era.
  • n. Any of various arbitrary units of time, especially:
  • n. Any of the divisions of the academic day.
  • n. Sports & Games A division of the playing time of a game.
  • n. Physics & Astronomy The time interval between two successive occurrences of a recurrent event or phases of an event; a cycle: the period of a satellite's orbit.
  • n. An instance or occurrence of menstruation.
  • n. A point or portion of time at which something is ended; a completion or conclusion.
  • n. The full pause at the end of a spoken sentence.
  • n. A punctuation mark ( . ) indicating a full stop, placed at the end of declarative sentences and other statements thought to be complete, and after many abbreviations.
  • n. A sentence of several carefully balanced clauses in formal writing.
  • n. A metrical unit of quantitative verse consisting of two or more cola.
  • n. An analogous unit or division of classical Greek or Latin prose.
  • n. Music A group of two or more phrases within a composition, often made up of 8 or 16 measures and terminating with a cadence.
  • n. Mathematics The least interval in the range of the independent variable of a periodic function of a real variable in which all possible values of the dependent variable are assumed.
  • n. Mathematics A group of digits separated by commas in a written number.
  • n. Mathematics The number of digits that repeat in a repeating decimal. For example, 1/7 = 0.142857142857 . . . has a six-digit period.
  • n. Chemistry A sequence of elements arranged in order of increasing atomic number and forming one of the horizontal rows in the periodic table.
  • adj. Of, belonging to, or representing a certain historical age or time: a period piece; period furniture.
  • interj. Used to emphasize finality, as when expressing a decision or an opinion: You're not going to the movies tonight, period!

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Appropriate for a given historical era.
  • adj. Set in and designed to evoke a particular historical period, especially through the use of elaborate costumes and scenery.
  • interj. And nothing else; and nothing less; used for emphasis.
  • n. The punctuation mark “.” (indicating the ending of a sentence or marking an abbreviation).
  • n. A Drosophila gene which gene product is involved in regulation of the circadian rhythm
  • n. two phrases (an antecedent and a consequent phrase)
  • v. To come to a period; to conclude.

from the GNU version of the Collaborative International Dictionary of English

  • n. A portion of time as limited and determined by some recurring phenomenon, as by the completion of a revolution of one of the heavenly bodies; a division of time, as a series of years, months, or days, in which something is completed, and ready to recommence and go on in the same order.
  • n. A stated and recurring interval of time; more generally, an interval of time specified or left indefinite; a certain series of years, months, days, or the like; a time; a cycle; an age; an epoch.
  • n. One of the great divisions of geological time. See the Chart of Geology.
  • n. The termination or completion of a revolution, cycle, series of events, single event, or act; hence, a limit; a bound; an end; a conclusion.
  • n. A complete sentence, from one full stop to another; esp., a well-proportioned, harmonious sentence.
  • n. The punctuation point [.] that marks the end of a complete sentence, or of an abbreviated word.
  • n. One of several similar sets of figures or terms usually marked by points or commas placed at regular intervals, as in numeration, in the extraction of roots, and in circulating decimals.
  • n. The time of the exacerbation and remission of a disease, or of the paroxysm and intermission.
  • n. A complete musical sentence.
  • intransitive v. To come to a period; to conclude. [Obs.] “You may period upon this, that,” etc.
  • transitive v. To put an end to.

from The Century Dictionary and Cyclopedia

  • To put an end to.
  • To end; cease.
  • n. A circuit: a round; hence, the time in which a circuit or revolution, as of a heavenly body, is made; the shortest interval of time within which any phenomenon goes through its changes of pass through them again immediately as before.
  • n. Any round of time, or series of years, days, etc.
  • n. An indefinite part of any continued state, existence, or series of events; an epoch: as, the first period of life; the last period of a king's reign; the period of the French revolution.
  • n. The point of completion of a cycle of years or round or series of events; limit; end; conclusion; termination.
  • n. Hence— The end to be attained; goal.
  • n. In rhetoric, a complete sentence from one full stop to another; a passage terminated by a full pause.
  • n. In ancient prosody, a group of two or more cola.
  • n. In music, a definite and complete division of a composition, usually consisting of two or more contrasted or complementary phrases; a complete musical sentence.
  • n. The point or character that marks the end of a complete sentence, or indicates an abbreviation, etc.; a full stop, thus(.).
  • n. In math.: The smallest constant difference which, added to the value of a variable, will leave that of a function (of which it is said to be the period) unchanged.
  • n. In vulgar arithmetic, one of several similar sets of figures or terms, marked by points or commas placed regularly after a certain number, as in numeration, in circulating decimals, and in the extraction of roots. Sometimes called degree.
  • n. In medicine, one of the phases or epochs which are distinguishable in the course of a disease.
  • n. Duration, continuance, term.
  • n. Bound, determination.
  • n. plural The menses.
  • n. In physical, the time of one complete oscillation or cycle of a periodic motion; the reciprocal of the frequency of a periodic motion.
  • n. In astronomy, the time of the revolution of a planet or satellite around its primary. Also orbital period.
  • n. In geology, technically, one of the larger divisions of geologic time of either the second or the third order, measured by the time of deposition of a ‘group’ or ‘system’ of formations, and characterized by the presence of a number of allied and similar faunas which as a whole differ from those of other periods.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a unit of geological time during which a system of rocks formed
  • n. (ice hockey) one of three divisions into which play is divided in hockey games
  • n. a punctuation mark (.) placed at the end of a declarative sentence to indicate a full stop or after abbreviations
  • n. an amount of time
  • n. the interval taken to complete one cycle of a regularly repeating phenomenon
  • n. the end or completion of something
  • n. the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause


from The American Heritage® Dictionary of the English Language, 4th Edition

Middle English periode, from Old French, from Medieval Latin periodus, from Latin perihodos, rhetorical period, from Greek periodos, circuit : peri-, peri- + hodos, way.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English periode, from Middle French periode, from Medieval Latin periodus, from Ancient Greek περίοδος (períodos, "circuit, period of time, path around"), from περί- (peri-, "around") + ὁδός (hodós, "way"). Displaced native Middle English tide ("interval, period, season"), from Old English tīd ("time, period, season"), Middle English elde ("age, period"), from Old English ieldu ("age, period of time").


  • The RE is, at least as I understand it (and in 40 years of statistics and econometrics I never ran in to it until started reading climate papers), is 1 minus the ratio of the predicted minus actual values (both in the verification period) squared over the squared deviations of the actual values (in the verification period) less the mean of the __calibration period__.

    Wahl and Ammann Again #1 « Climate Audit

  • It is going to make a difference which 5-year period is picked or whether the trend rate measured over a 5-year period of a 10-year period….


  • Here it is usual to enquire, whether it is necessary to attend to our numbers through the whole compass of a period, [Footnote: Our author here informs us, that what the Greeks called [Greek: periodos], a _period_, was distinguished among the Romans by the words _ambitus, circuitus, comprehensio, continuatio_, and _circumscriptio_.

    Cicero's Brutus or History of Famous Orators; also His Orator, or Accomplished Speaker.

  • In the first period of childhood, the first year of life may be further distinguished as the _period of infancy_. [

    The Sexual Life of the Child

  • "Our findings show that the term period should not be treated uniformly; infants born at early term are a higher-risk group than those born at full term."

    The Seattle Times

  • Billed as "among the first of its kind offered on a fixed-index annuity," the strategy takes the closing price of gold on the last day of the term period and compares it with the price at the beginning of the term.

  • Thanks to, it's in fact possible to issue also an high risk or a smokers life insurance, with no need of exam: all you need to do is to compile the little form online specifying what you are searching for like the term period and the coverage amount and evaluate the offered solutions.

    Archive 2008-07-01

  • Writing the word period at the end of a sentence uses the name of a punctuation mark to emphasize the work of a punctuation mark; in this case, writing period stresses finality or inescapa-bility.

    The Right Word in the Right Place at the Right Time

  • Under the term period, no principal payments would be required until April 29, 2011.

    Marketwire - Breaking News Releases

  • During the term period, no principal payments would be required until April 29, 2011.

    Marketwire - Breaking News Releases


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  • (n): any of several bodily processes by which substances go out of the body

    WeirdNet is a great gender equalizer. In its radical sweep, women have attained foreskins and men periods.

    July 26, 2009

  • I thought in the morning you're supposed to wash it with cold running water, then cook with soy sauce.

    July 26, 2009

  • Put period in a saucer of vinegar and leave it overnight to soften. In the morning, chuck it out.

    July 24, 2009

  • Personally, I use " as quotation marks and ' as emphasis, but then I'd put the period (which I usually call a full stop) outside, like: 'FROG BLOG'.

    July 24, 2009

  • Yes. Inside or outside. In this instance, however, I thought I was adding the quotes for emphasis, but it clearly appears to be a title. I'm very confused.

    July 24, 2009

  • Do you mean to ask whether the period goes inside or outside the closing quotation mark? If so, it can depend on whether you're British or American. Americans tend to put it inside; British tend to put it outside. :-)

    July 24, 2009

  • Help me settle this. I say the period goes after "FROG BLOG" in this instance, but I'm being told otherwise. SEE 100th BLOG POST

    July 24, 2009

  • capitalize every sentence and end it with a period

    January 25, 2007