Period

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

• Era, a length or span of time
• Full stop or period, a punctuation mark

Science

• Wave period, the time taken for one full oscillation
• Orbital period, the time for one object to complete an orbit around another
• Period (periodic table), a horizontal row of the periodic table
• Menstruation, is sometimes referred to as a "period" as it is the periodic discharge of blood and mucosal tissue (the endometrium) from the uterus and vagina
• Period (gene), a gene in Drosophila involved in regulating circadian rhythm
• Period (geology), a subdivision of geologic time

Mathematics

• Periods (ring), members of the ring of numbers that can be expressed as integrals of algebraic differential forms over algebraically defined domains
• Periodic point, a point that is visited by a dynamic system with a certain period (frequency)

Arts

• Period piece, a creative work set in a particular era
• Period (music), a concept in musical composition
• Period, the final book in Dennis Cooper's George Miles cycle of novels
• Period furniture, period clothing, etc., usually referring to antique items, or copies of antiques; used in furnishing an old building or in a stage or film production, to lend authenticity to the setting by reflecting the specific era of the architecture or the story

Academics

• Period (school), a class meeting time in schools

Sports

• Periods in ice hockey; see Ice hockey#Periods and overtime

See also

• Duration (disambiguation)
• Periodization
• Full stop (disambiguation)
• Periodicity (disambiguation)