synchronous

adjective

syn·​chro·​nous ˈsiŋ-krə-nəs 

ˈsin-

1

: happening, existing, or arising at precisely the same time

2

: recurring or operating at exactly the same periods

3

: involving or indicating synchronism

4

a

: having the same period

also : having the same period and phase

b

: geostationary

5

: of, used in, or being digital communication (as between computers) in which a common timing signal is established that dictates when individual bits can be transmitted and which allows for very high rates of data transfer

synchronously adverb

synchronousness noun

Did you know?

Communications satellites are usually put into a synchronous (or geosynchronous) orbit, circling the earth once every 24 hours and so appearing to hover over a single spot on the surface. This type of synchronized movement is important, since you have to know where to aim your satellite dish. In the computer field, synchronous usually refers to the use of a simple timing signal that permits very rapid exchange of data between computers. The kind of mysterious coincidence sometimes called synchronicity—such as the appearance of two different comic-strip characters named Dennis the Menace in the U.S. and Britain within three days of each other in 1951—has fascinated people for centuries.

Synonyms

• concurrent
• synchronic
• coincident
• simultaneous

Choose the Right Synonym for synchronous

contemporary, contemporaneous, coeval, synchronous, simultaneous, coincident mean existing or occurring at the same time.

contemporary is likely to apply to people and what relates to them.

Abraham Lincoln was contemporary with Charles Darwin

contemporaneous is more often applied to events than to people.

contemporaneous accounts of the kidnapping

coeval refers usually to periods, ages, eras, eons.

two stars thought to be coeval

synchronous implies exact correspondence in time and especially in periodic intervals.

synchronous timepieces

simultaneous implies correspondence in a moment of time.

the two shots were simultaneous

coincident is applied to events and may be used in order to avoid implication of causal relationship.

the end of World War II was coincident with a great vintage year

Examples of synchronous in a Sentence

the synchronous arrival of a baby sister and loss of a beloved grandmother strongly affected the child

Recent Examples on the Web

That’s highly synchronous, resulting in many, many animals making that migration simultaneously. —Noël Fletcher, Forbes.com, 23 May 2025

The sheer number of DNA shifts that must have occurred in rapid succession to create this synchronous outcome also reflects the strong pressure horses were likely under to become fast and tireless. —Lauren Leffer, Popular Science, 27 Mar. 2025

The key lies in a fast oscillating sheet known as a diffuser, onto which synchronous images are projected at high speed (2,880 images per second) and at different heights; human persistence of vision ensures that these images are perceived as true 3D objects. —ArsTechnica, 30 Apr. 2025

Students engage in 3–4 hours of daily synchronous classes, including discussions of classic and contemporary texts, writing workshops to hone analytical essays, and adaptive STEM programs like Beast Academy. —Ray Ravaglia, Forbes.com, 24 Apr. 2025

Word History

Etymology

borrowed from Late Latin synchronos "contemporary," borrowed from Greek sýnchronos "existing at the same time," from syn- syn- + -chronos, adjective derivative of chrónos "time, duration," of obscure origin

First Known Use

1669, in the meaning defined at sense 1

Phrases Containing synchronous

• synchronous motor

Rhymes for synchronous

• asynchronous
• geosynchronous

Kids Definition

synchronous

adjective

syn·​chro·​nous ˈsiŋ-krə-nəs 

ˈsin-

: happening or existing at the same time : simultaneous

Etymology

from Latin synchronos "synchronous," from Greek synchronos (same meaning), from syn- "together, along with" and chronos "time" — related to chronicle, synonymous

Medical Definition

synchronous

adjective

syn·​chro·​nous ˈsiŋ-krə-nəs, ˈsin- 

1

: happening, existing, or arising at precisely the same time

2

: recurring or operating at exactly the same periods

3

: having the same period

also : having the same period and phase

synchronously adverb