English Reference

Word

synchronous

Phoneticssyn·chro·nous

US/ˈsɪŋkɹənəs/

UK/sˈɪnkɹənəs/

Definitions

01happening at the same time

C1 · Science

adj. happening, existing, or moving at exactly the same time or speed.

adj. occurring, existing, or operating at the same time or rate. Often used in physics or engineering to describe waves or mechanical parts.

“The dancers moved in synchronous motion, perfectly matching each other's steps.”

“The synchronous rotation of the moon ensures that the same side always faces the Earth as it completes its orbit.”

Academic · Technical

Usage

Usually placed before the noun or after a linking verb like 'be'.

Antonyms

02computing/blocking

C1 · Computing

adj. a way of running computer tasks where one thing must finish before the next one can start.

adj. referring to a process that blocks other operations until it completes; execution occurs in a sequential, predictable time-step.

“The program felt slow because it was using a synchronous connection to the database.”

“In a synchronous execution model, the main thread is blocked until the function returns, potentially causing the user interface to freeze during long operations.”

Technical

Usage

Commonly used to describe functions, calls, or communication protocols.

Teaching tip

In modern software development, this is often contrasted with 'asynchronous' (async) programming which allows multiple tasks to run at once.

Antonyms

asynchronousnon-blocking

Real-World Examples

“The prehistoric ritual of ecstatic, synchronous dancing is being quietly eroded, and the modern mind is paying for it.”
The Guardian · 14 Aug 2026
“By contrast, he sees a world model as a synchronous, real-time system.”
Ars Technica · 13 Jul 2026

Etymology

Borrowed from Late Latin synchronus, from Ancient Greek σύγχρονος (súnkhronos, “contemporaneous”), from σῠν- (sŭn-, “with, together”) + χρόνος (khrónos, “time”). By surface analysis, syn- + chron- + -ous = synchrony + -ous; however, all related words (e.g., synchronic, synchrony, synchronicity, diachronous, diachronic, diachrony, diachronicity) were coined later, either as back-formations from, or otherwise by analogy with the surface analysis of, synchronous.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

Domain

Computing

This entry

Level
C1 · Advanced
Frequency
Occasional
Updated

Scan code

englishreference.com/q/synchronous

English Reference