Definition of "period" []

• An interval of time characterized by the occurrence of a certain condition, event, or phenomenon: a period of economic prosperity. (noun)
• An interval of time characterized by the prevalence of a specified culture, ideology, or technology: artifacts of the pre-Columbian period. (noun)
• An interval regarded as a distinct evolutionary or developmental phase: Picasso's early career is divided into his blue period and rose period. (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)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "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__."
• "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_."