period

Etymology

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

noun

1. A length of time.
   There was a period of confusion following the announcement.
   You'll be on probation for a six-month period.
   Philip Miles, defending, said: "This was a single instance, there was no allegation of continuing behaviour over a long period of time." December 14, 2011, Steven Morris, “Devon woman jailed for 168 days for killing kitten in microwave”, in Guardian
2. A length of time in history seen as a single coherent entity; an epoch, era.
   Food rationing continued in the post-war period.
3. (now chiefly Canada, US, Philippines) The punctuation mark “.” (indicating the ending of a sentence or marking an abbreviation).
   ‘You know, a period? The black spot at the end of a sentence — what do you call them over there?’ 2002, Zadie Smith, The Autograph Man, Penguin Books (2003), page 299
4. (figurative) A decisive end to something; a stop.
5. The length of time during which the same characteristics of a periodic phenomenon recur, such as the repetition of a wave or the rotation of a planet.
6. (euphemistic) Female menstruation; an episode of this.
   When she is on her period, she prefers not to go swimming.
7. A section of an artist's, writer's (etc.) career distinguished by a given quality, preoccupation etc.
   This is one of the last paintings Picasso created during his Blue Period.
8. Each of the divisions into which a school day is split, allocated to a given subject or activity.
   I have math class in second period.
9. (sports, chiefly ice hockey) Each of the intervals, typically three, of which a game is divided.
   Gretzky scored in the last minute of the second period.
10. (sports, chiefly ice hockey) One or more additional intervals to decide a tied game, an overtime period.
    They won in the first overtime period.
11. (obsolete, medicine) The length of time for a disease to run its course.
12. An end or conclusion; the final point of a process etc.
    […]and yet this is but the ἀρχή ὠδίνων, the Beginning of those evils which shall never End till eternity hath a period[…] a. 1667, Jeremy Taylor, “Advent Sunday Dooms-Day Book: Or, Christ’s Advent to Judgement”, in Ἐνιαυτος: A Course of Sermons for All the Sundays Of the Year, London: R. Norton, published 1673, page 8
13. (rhetoric) A complete sentence, especially one expressing a single thought or making a balanced, rhythmic whole.
    Periods are beautiful when they are not too long. 1641, Ben Jonson, Timber
14. (obsolete) A specific moment during a given process; a point, a stage.
    The Death of Patroclus was the most eminent Period; and consequently the most proper Time for such Games. 1720, Alexander Pope, translating Homer, Iliad, Book IV (note 125)
15. (chemistry) A row in the periodic table of the elements.
16. (geology) A geochronologic unit of millions to tens of millions of years; a subdivision of an era, and subdivided into epochs.
    These fossils are from the Jurassic period.
17. (genetics) A Drosophila gene, the gene product of which is involved in regulation of the circadian rhythm.
    Polyclonal antibodies were prepared against the period gene product, which influences biological rhythms in D. melanogaster, by using small synthetic peptides from the per sequence as immunogens. 1 April 1988, “Antibodies to the period gene product of drosophila reveal diverse tissue distribution and rhythmic changes in the visual system”, in Neuron, volume 1, number 2, page 141
18. 20 November 2009, “Gene Dmel\per”, in FlyBase (Gene Report (database record)), The FlyBase Consortium, retrieved 2009-12-07:
19. (music) Two phrases (an antecedent and a consequent phrase).
20. (mathematics) The length of an interval over which a periodic function, periodic sequence or repeating decimal repeats; often the least such length.
21. (archaic) End point, conclusion.
    As thus all gazed on hir, so she glaunced hir lookes on all, surueying them as curiously, as they noted hir exactly, but at last she set downe her period on the face of Alexis […] 1590, Robert Greene, “The Shepheards Tale”, in Greenes Mourning Garment, London: Thomas Newman, page 17
    When Loue thus in his Center ends, Desire and Hope, his inward friends Are shaken off: while Doubt and Griefe, The weakest giuers of reliefe, Stand in his councell as the chiefe: And now he to his period brought, From Loue becomes some other thought. 1629, John Beaumont, “A Description of Love”, in Bosworth-field with a Taste of the Variety of Other Poems, London: Henry Seile, page 100
    Set up an hour-glasse; hee’l go on untill The last sand make his Period. 1651, William Cartwright, The Ordinary, London: Humphrey Moseley, act III, scene 5, page 51

adj

1. Designating anything from a given historical era.
   a period car
   a period TV commercial
2. Evoking, or appropriate for, a particular historical period, especially through the use of elaborate costumes and scenery.
   As the guests arrived — there were about a hundred, a majority in period attire — I began to feel out of place in my beige summer suit, white shirt, and red necktie. Then I got over it. I certainly didn't suffer from Confederate-uniform envy. 2004, Mark Singer, Somewhere in America, Houghton Mifflin, page 70

intj

1. (chiefly Canada, US) That's final; that's the end of the matter (analogous to a period ending a sentence); end of story.
   I know you don't want to go to the dentist, but your teeth need to be checked, period!

verb

1. (obsolete, intransitive) To come to a period; to conclude.
   For you may period upon this, that where there is the most pity for others, there is the greatest misery in the party pitied.
2. (obsolete, transitive, rare) To put an end to.