from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun An interval of time characterized by the occurrence of a certain condition, event, or phenomenon.
  • noun An interval of time characterized by the prevalence of a specified culture, ideology, or technology.
  • noun An interval regarded as a distinct evolutionary or developmental phase.
  • noun Geology A unit of time, longer than an epoch and shorter than an era.
  • noun Any of various arbitrary units of time, especially.
  • noun Any of the divisions of the academic day.
  • noun Sports & Games A division of the playing time of a game.
  • noun Physics & Astronomy The time interval between two successive occurrences of a recurrent event or phases of an event; a cycle.
  • noun A point or portion of time at which something is ended; a completion or conclusion.
  • noun 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.
  • noun The full pause at the end of a spoken sentence.
  • noun A sentence of several carefully balanced clauses in formal writing.
  • noun A metrical unit of quantitative verse consisting of two or more cola.
  • noun An analogous unit or division of classical Greek or Latin prose.
  • noun Music A group of two or more phrases within a composition, often made up of 8 or 16 measures and terminating with a cadence.
  • noun 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.
  • noun A group of digits separated by commas in a written number.
  • noun The number of digits that repeat in a repeating decimal. For example, 1/7 = 0.142857142857 … has a six-digit period.
  • noun Chemistry A sequence of elements arranged in order of increasing atomic number and forming one of the horizontal rows in the periodic table.
  • adjective Of, belonging to, or representing a certain historical age or time.
  • interjection Used to emphasize finality, as when expressing a decision or an opinion.

from The Century Dictionary.

  • To put an end to.
  • To end; cease.
  • noun plural The menses.
  • noun In physical, the time of one complete oscillation or cycle of a periodic motion; the reciprocal of the frequency of a periodic motion.
  • noun In astronomy, the time of the revolution of a planet or satellite around its primary. Also orbital period.
  • noun 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.
  • noun 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.
  • noun Any round of time, or series of years, days, etc.
  • noun 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.
  • noun The point of completion of a cycle of years or round or series of events; limit; end; conclusion; termination.
  • noun Hence— The end to be attained; goal.
  • noun In rhetoric, a complete sentence from one full stop to another; a passage terminated by a full pause.
  • noun In ancient prosody, a group of two or more cola.
  • noun In music, a definite and complete division of a composition, usually consisting of two or more contrasted or complementary phrases; a complete musical sentence.
  • noun The point or character that marks the end of a complete sentence, or indicates an abbreviation, etc.; a full stop, thus(.).
  • noun 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.
  • noun 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.
  • noun In medicine, one of the phases or epochs which are distinguishable in the course of a disease.
  • noun Duration, continuance, term.
  • noun Bound, determination.

from the GNU version of the Collaborative International Dictionary of English.

  • noun 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.
  • noun 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.
  • noun (Geol.) One of the great divisions of geological time. See the Chart of Geology.
  • noun The termination or completion of a revolution, cycle, series of events, single event, or act; hence, a limit; a bound; an end; a conclusion.
  • noun (Rhet.) A complete sentence, from one full stop to another; esp., a well-proportioned, harmonious sentence.
  • noun (Print.) The punctuation point [.] that marks the end of a complete sentence, or of an abbreviated word.


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").


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  • 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 2006

  • 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….

    Automation Michael, Donald N. 1965

  • 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. Marcus Tullius Cicero

  • 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 Albert Moll 1900

  • "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 2011

  • 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.

    unknown title 2011

  • 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 2008

  • 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 William Safire 2004

  • 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 William Safire 2004

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

    Marketwire - Breaking News Releases 2009


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  • capitalize every sentence and end it with a period

    January 25, 2007

  • 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

  • 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

  • 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

  • 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

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

    July 24, 2009

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

    July 26, 2009

  • (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