periodic

Etymology

It is partly borrowed from French périodique and partly borrowed from Latin periodicus (“intermittent”),^[2][3][4] from Ancient Greek περιοδικός (periodikós, “recurring, intermittent”),^[2][3] from περίοδος (períodos, “circuit, cycle, period”) and the suffix -ικός (-ikós).^[2][3] The Greek noun is formed from περι- (peri-, “around”) and ὁδός (hodós, “way”), and is the source of period.^[5] In Middle French the adjective was used of recurring symptoms from the 15th century, of the motion of a celestial body from 1634, of a style using rhetorical periods from 1671 and of magazines from 1721;^[2] in Latin it is first recorded in Pliny, of fevers.^[2] Etymonline calls the Latin form Late Latin.^[5] The English word periodical is older.^[2]

Earliest recorded meaning

Of or relating to the recurring motion of a celestial body in its orbit: 1650, in J. Howell's Instructions for Forreine Travell.^[2][4] Etymonline dates the sense "proceeding in a series of successive revolutions" to the 1640s,^[5] and Merriam-Webster gives 1650.^[3]

Semantic evolution

From the cycles of the heavens the word passed to medicine, of symptoms that recur at regular intervals (1661),^[2] and then to anything recurring regularly, or more loosely from time to time (1750 in the OED, the 1660s in Etymonline).^[2][5] In 1701 it was also used of a style built on rhetorical periods, elevated and formal.^[2][6] The 19th century brought scientific senses: a periodic function in mathematics (1820), physical phenomena that repeat in time or space (1836), and in chemistry the regular recurrence of the properties of the elements (1872, in periodic law).^[2][5] The periodic table (1889) is so called because elements with similar properties recur at intervals in the table.^[5][4] From 1884 it could also mean "relating to a particular period of history".^[2]

Timeline

• 1640s – proceeding in successive revolutions, in Etymonline.^[5]
• 1650 – of the recurring motion of a celestial body.^[2][3]
• 1661 – in medicine, of regularly recurring symptoms.^[2]
• 1701 – of style, using rhetorical periods.^[2]
• 1750 – recurring at regular intervals, or intermittently.^[2]
• 1820 – in mathematics, of a periodic function.^[2]
• 1836 – in physics, regularly repeating in time or space.^[2]
• 1872 – in chemistry, periodic law.^[2][5]
• 1884 – relating to a particular period of history.^[2]
• 1889 – periodic table.^[5]

Meanings

Adjective

1. Happening at regular intervals: periodic checks on the boiler.^[7][3][2]
2. Happening from time to time; recurrent or intermittent: The district suffers periodic floods.^[3][7][2]
3. Made up of a series of stages repeated regularly; cyclic.^[3][7]
4. (chemistry) Relating to the periodic table or to the regular recurrence of the properties of the elements.^[6][2][4]
5. (mathematics) Of a function, returning to the same value at constant intervals.^[2][4]
6. (physics) Varying so that the same state is regularly repeated in time or space.^[2]
7. (astronomy) Relating to the revolution of a celestial body in its orbit.^[2][4]
8. Of style, written in rhetorical periods; formal and elaborate.^[6][2]

Word family

• periodically
• antiperiodic
• nonperiodic
• quasiperiodic
• thermoperiodic
• unperiodic
• aperiodic

Related words

• period
• periodicity
• periodical

Usage notes

In chemistry periodic (/ˌpəːrʌɪˈɒdɪk/) also names periodic acid, an oxoacid of iodine richer in oxygen than iodic acid; it is formed from per- and iodic and is recorded from 1836.^[2][4]

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z 27 28 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g h Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c d e f g Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b c d e f g h i Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b c Soanes, Catherine; Stevenson, Angus, eds. (2004), Concise Oxford English Dictionary, 11th ed., Oxford: Oxford University Press
7. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins