synchronous

Etymology

It is borrowed from Late Latin synchronus (“simultaneous”),^{[2][3][4][5][6]} from Ancient Greek σύγχρονος (súnkhronos, “happening at the same time”),^[2][3][4] formed from σύν (sún, “together, with”) and χρόνος (khrónos, “time”),^[2][4][5] with the suffix -ous.^[2][7][6] Barnhart calls the origin of the Greek word for time uncertain.^[8]

Earliest recorded meaning

Existing or happening at the same time; contemporary, simultaneous: 1669, in T. Gale's Court of the Gentiles.^[2][9][3]

Semantic evolution

From "happening at the same time" the word moved in 1677 to things that recur at the same instants or go on at the same rate.^[2][4] Johnson (1755) defined it simply as happening at the same time, quoting Arbuthnot on the air.^[10] Later uses are technical: of uniform velocity (1785), of tables or histories that set contemporary events side by side (1823), of a curve in geometry (1867), of alternating currents and motors that keep time with them (1897), and, in linguistics, the same as synchronic (1936).^[2] In computing and telecommunications it has meant since 1954 working by equally spaced timing pulses, and since 1961 a satellite or orbit that keeps pace with the planet's rotation.^[2]

Timeline

• 1669 – existing or happening at the same time; simultaneous.^[2][9][3]
• 1677 – recurring at the same instants; keeping time together.^[2] Etymonline dates it to the 1670s.^[4]
• 1785 – of uniform velocity.^[2]
• 1823 – treating together events of the same period.^[2]
• 1867 – in geometry, of a curve joining the points reached at one instant by particles descending a family of curves.^[2]
• 1897 – of alternating currents with coincident periods, and of motors working in time with them.^[2]
• 1936 – in linguistics, synchronic.^[2]
• 1954 – in computing, using equally spaced pulses to time operations.^[2]
• 1961 – of a satellite or orbit, keeping pace with the planet's rotation.^[2]

Meanings

Adjective

1. Happening or existing at the same time; simultaneous or contemporary: The two uprisings were synchronous.^[9][11][2]
2. Recurring or operating at exactly the same rate and moment: the synchronous strokes of the rowers.^[11][9][2]
3. In physics, of periodic things such as voltages: having the same frequency and phase.^[11][2]
4. In computing and telecommunications, timed by equally spaced pulses.^[2]
5. Of a satellite or orbit: going round a planet at the rate at which the planet turns; geosynchronous.^[2]
6. In linguistics, synchronic.^[2]

Word family

• synchronously
• synchronousness
• unsynchronous
• synchroneity
• asynchronous
• geosynchronous
• nonsynchronous
• synchronous rotation

Related words

• diachronic
• synchronize
• synchrony
• synchronic
• synchronicity
• chronic
• chronology
• anachronism

References

1. ^ 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 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
4. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
6. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
7. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
9. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
10. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
11. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins