Period

Period (from Greek περίοδος) or periodic may refer to:

• Timeframe, a length or era of time
• Full stop, also called a period – a dot at the end of a sentence

Science

• Periodic acid, an oxoacid of iodine (from "per" + "iodic")
• Period (physics), the time taken for one full oscillation; it is the reciprocal of frequency
• Orbital period, the time for one object to complete an orbit around another
• Periodic table, a chart which lists all currently known chemical elements
  • Period (periodic table), a horizontal row of the periodic table
• Menstruation, a phase of the menstrual cycle in which the uterine lining is shed
• Period (gene), a gene in Drosophila involved in regulating circadian rhythm
• Period (geology), a subdivision of geologic time
• Period of time in the study of history

Mathematics

• Periodic (or periodical) function, one that repeats its values in regular intervals
  • The period of a periodic function
    • The nth Pisano period, π(n), is the period with which the sequence of Fibonacci numbers modulo n repeats.
• Periodic group, another name for a torsion group
• Periods (ring) — members of the ring of numbers that can be expressed as integrals of algebraic differential forms over algebraically defined domains
• Period of an orbit

Language

• Period (punctuation), a punctuation mark indicating the end of a sentence or phrase, specifically, a dot.
• Periodic sentence, a sentence that is not grammatically complete until its end

Arts

• Period piece, a creative work set in a particular era
• Costume drama, also known as "period drama", filmed historical drama featuring elaborate costumes and sets
• Period (music), a concept in musical composition
• Period, the final book in Dennis Cooper's George Miles cycle of novels

Academics

• Period (school), a class period in schools

Sports

• Periods in ice hockey, intervals into which a match is divided

Other meanings

• Periodicity, the quality of occurring at regular intervals or periods

See also

• Periodization
• Full stop (disambiguation)