Definition of period in English:

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Pronunciation: /ˈpirēəd/


1A length or portion of time: he had long periods of depression the ale will be available for a limited period the period 1977–85 the training period is between 16 and 18 months
More example sentences
  • The fluvial sediments, however, represent rapid deposition in relatively short periods (days or months).
  • Hauling and applying manure may require large blocks of time for relatively short periods throughout the year.
  • Generally, consumers have accepted the relatively short periods of 14 to 21 days for half or full gallons of milk.
time, spell, interval, stretch, term, span, phase, bout, run, duration, chapter, stage;
while, patch
1.1A portion of time in the life of a person, nation, or civilization characterized by the same prevalent features or conditions: the early medieval period
More example sentences
  • Life at the bottom of society was always difficult in the late medieval and early modern periods: but around 1600 conditions for many of the poor were terrible.
  • His work has focused on the medieval and early modern periods.
  • Of these, 98 per cent cover the 19th and 20th centuries, while only 16 per cent cover medieval or earlier periods.
era, age, epoch, time, days, years;
Geology  eon
1.2One of the set divisions of the day in a school allocated to a lesson or other activity.
Example sentences
  • I would look at it later and make sense of it but, as for now, I had to get to my next lesson because the free period would probably be nearing an end.
  • The total lesson takes several class periods and I recite the poems to motivate my young artists many times throughout the lesson.
  • To accommodate the rich level of activity hoped for in his mathematical laboratory, he proposed that two consecutive class periods be allocated to it.
lesson, class, session
1.3Each of the intervals into which the playing time of a sporting event is divided.
Example sentences
  • In the first period of extra time both teams played at a frenetic pace with tenacious defending keeping Keighley's hopes alive.
  • There is an extra period called injury time, usually in the vicinity of three minutes.
  • If games are tied at full-time an extra period will be played with the first team to score winning the game.
1.4A major division of geological time that is a subdivision of an era and is itself subdivided into epochs, corresponding to a system in chronostratigraphy.
Example sentences
  • Because of this, clay becomes progressively less common in older geological periods and is almost never found in Precambrian formations.
  • The following table shows the three eras and eleven geological periods that comprise the Phanerozoic.
  • This book shows the dynamic effects of the many periods of Pleistocene glacial advance and melting on the geology and topography of the northwestern United States.
2North American A punctuation mark (.) used at the end of a sentence or an abbreviation.
Example sentences
  • As he talked he jabbed the lit end of his cigar into the air as though he were punctuating his sentences by burning periods in the air.
  • Simple input issues such as periods or abbreviations would make older databases think it was a new entry.
  • We use American punctuation standards - put your commas and periods inside your quotation marks.
2.1 informal, chiefly North American Added to the end of a statement to indicate that no further discussion is possible or desirable: he is the sole owner of the trademark, period
More example sentences
  • "You hate cats period, " Tiffany reminded her fondly.
  • He could simply have said he favours public ownership, full stop, period.
3 Physics The interval of time between successive occurrences of the same state in an oscillatory or cyclic phenomenon, such as a mechanical vibration, an alternating current, a variable star, or an electromagnetic wave.
Example sentences
  • To produce a larger effect, the motion must accumulate, and for wave-impulses to accumulate, they must arrive in periods identical with the periods of vibration of the atoms on which they impinge.
3.1 Astronomy The time taken by a celestial object to rotate around its axis, or to make one circuit of its orbit.
Example sentences
  • The atmosphere rotates with periods ranging from over 18 hours near the equator to faster than 13 hours near the poles.
  • In contrast, Jupiter-family comets tend to have predictable, well-determined orbits with short periods and low inclinations.
  • The first problem Galileo attacked at Florence was to determine orbits and periods for Jupiter's four satellites.
3.2 Mathematics The interval between successive equal values of a periodic function.
Example sentences
  • What is the period of the continued fractions of the following numbers?
  • In 1834 Jacobi proved that if a single-valued function of one variable is doubly periodic then the ratio of the periods is imaginary.
4 (also menstrual period) A flow of blood and other material from the lining of the uterus, lasting for several days and occurring in sexually mature women who are not pregnant at intervals of about one lunar month until the onset of menopause.
Example sentences
  • It is common to have heavy blood flow at the beginning of a period and lighter blood flow at the end.
  • It mostly affects women between the ages of 50 and 70, who have been through the menopause (when your periods stop).
  • Women may also experience painful periods and pain during sexual intercourse.
menstruation, menstrual flow, menses
informal the curse, time of the month, monthlies
5 Chemistry A set of elements occupying an entire horizontal row in the periodic table.
Example sentences
  • The horizontal rows or periods also have predictable trends in characteristics because as you move left to right in a row only one electron is added changing the atomic number by one.
  • As we move down the periods, the elements have a greater atomic weight.
6 Rhetoric A complex sentence, especially one consisting of several clauses, constructed as part of a formal speech or oration.
Example sentences
  • There is frequently poor closure of periods and an inept employment of rhythm in the closure of stanzas and of poems.
6.1 Music A complete idea, typically consisting of two or four phrases.
Example sentences
  • His's an oceanic performance that gives emphasis to the work's undulating hemiolas as they reach across bar lines and destabilize phrase periods.


Belonging to or characteristic of a past historical time, especially in style or design: a splendid selection of period furniture
More example sentences
  • This house is a great blend of period qualities and contemporary design.
  • One of the highlights of the weekend will be period re-enactments of historical trials in the old Law Courts in City Hall.
  • A home that has both period style and modern comforts - is it perfection?


Late Middle English (denoting the time during which something, especially a disease, runs its course): from Old French periode, via Latin from Greek periodos 'orbit, recurrence, course', from peri- 'around' + hodos 'way, course'. The sense 'portion of time' dates from the early 17th century.

  • When first used, period referred to the time during which something such as a disease, ran its course. It goes back to Greek periodos ‘orbit, recurrence, course’, from peri- ‘around’ and hodos ‘way’. The sense ‘portion of time’ dates from the early 17th century, as does use of the word to mean ‘full stop’, now part of US English. Peri is also found in peripatetic (Late Middle English) now meaning ‘wandering, travelling’ but from Greek peripatetikos ‘walking up and down’ and originally applied to followers of the ideas of Aristotle (384–322 bc), who is said to have walked about while teaching; and periphery (late 16th century) originally the boundary of something. Hodos, the second part of period is also found in episode (late 17th century), literally ‘coming in beside’ from epi ‘addition’ and eisodos ‘entry’ (formed from eis ‘into’ and hodos); and exodus, ‘departure’ formed in the same way using ex- ‘out of’. See also method

For editors and proofreaders

Syllabification: pe·ri·od

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