# synchronous

/ˈsɪŋkɹənəs/ (US) · /sˈɪnkɹənəs/ (UK)

Source: https://englishreference.com/word/synchronous
Updated: 2026-08-27

## Senses

### 1. happening at the same time

adjective · CEFR C1 · Academic · Technical

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

For teachers: 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.

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

### 2. computing/blocking

adjective · CEFR C1 · Technical

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

For teachers: 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.

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.

## Examples

- The two clocks are perfectly synchronous.
- The software uses synchronous communication to ensure that the server and client update their data at the exact same moment.
- In a synchronous network, data packets are transmitted at regular intervals, allowing the receiver to predict exactly when to expect the next bit of information.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.