asynchronous

IPA/eɪˈsɪŋkrənəs/
KK[ˈesˈɪŋkrənəs]IPA/eɪˈsɪŋkrənəs/

asynchronous — adjective

  • asynchronouspositive
  • more asynchronouscomparative
  • most asynchronoussuperlative

1. occurring or taking place at a separate time from something else, without requir

1.adjectiveB2
Definition

occurring or taking place at a separate time from something else, without requiring both events to share the same moment or follow a matched pace.

Example

The two countries use an asynchronous election schedule so each votes on a different day.

In the asynchronous format, team members posted updates on a shared document rather than joining a call.

asynchronous meeting format — updates shared over time, not all at once

Common collocations
  • asynchronous schedule
  • asynchronous events
  • asynchronous timing
  • asynchronous relationship
Synonyms
  • unsynchronized

    less common; implies two things that could be aligned are no longer matched

  • offset

    describes events deliberately shifted in time rather than occurring independently

Antonyms
  • simultaneous

    means exactly at the same moment, whereas asynchronous means deliberately apart

  • synchronous

    implies coordinated or matched timing between events

Grammar Patterns

asynchronous + noun

be + asynchronous

2. used to describe an instructional format where learners work through pre-recorde

2.adjectiveB2
Definition

used to describe an instructional format where learners work through pre-recorded videos, readings, and tasks at times that suit them, instead of joining a live lesson held at a fixed hour.

Example

The university offers an asynchronous course where students watch recorded lectures and submit homework by Sunday midnight.

Dr. Yamamoto chose asynchronous teaching so that working parents could study after their children went to bed.

asynchronous teaching — flexible timing for learners with other commitments

Common collocations
  • asynchronous learning
  • asynchronous teaching
  • asynchronous course
  • asynchronous program
  • asynchronous class
Synonyms
  • self-paced

    emphasises the learner's freedom to control speed, not the absence of a shared schedule

  • on-demand

    focuses on the availability of materials whenever the learner chooses

Antonyms
  • synchronous

    describes live, real-time instruction where all participants meet simultaneously

Grammar Patterns

asynchronous + course / learning / teaching / class

Usage Note

Commonly paired with nouns such as 'learning', 'course', 'teaching', and 'program'. The opposite format is 'synchronous', where teacher and students meet at a fixed time, often via live video.

Common Mistakes

I joined an asynchronous class where we all meet on Zoom at 9 AM.
I joined an asynchronous class where I watch recorded videos at any time of day.
A class with a fixed live meeting time is synchronous, not asynchronous.

3. relating to a way of sending digital data in which the sending and receiving dev

3.adjectiveC1
Definition

relating to a way of sending digital data in which the sending and receiving devices do not rely on a shared timing signal, and each unit of data marks its own start and end.

Example

A keyboard uses asynchronous communication — each keystroke arrives with start and stop bits, not a shared clock.

asynchronous communication — data framed with start/stop bits, no shared clock

The technician set the modem to asynchronous mode so the devices did not need a shared timing signal.

Common collocations
  • asynchronous communication
  • asynchronous transmission
  • asynchronous transfer
  • asynchronous mode
  • asynchronous data
Synonyms
  • start-stop

    a more specific term for the framing method used in asynchronous serial communication

Antonyms
  • synchronous

    requires a shared clock signal between sender and receiver to coordinate data transfer

Grammar Patterns

asynchronous + communication / transmission / mode / transfer

asynchronous + noun

Usage Note

Technical term in computing and telecommunications. The opposite 'synchronous' transmission requires both devices to follow a shared clock signal. Not used in everyday conversation outside technical contexts.

Word family

  • asynchronously
    adverbB2
  • asynchrony
    nounC1
  • synchronous
    adjectiveB2
  • synchronize
    verbB2
  • synchronization
    nounC1

Synonym discussion

Sense: adjective/1

'Simultaneous' and 'synchronous' both describe events that happen at the same moment, but with a difference in emphasis: 'simultaneous' points to the bare time coincidence (two earthquakes striking at the same second), while 'synchronous' suggests deliberate coordination or matched pace (synchronous swimmers moving as one). 'Concurrent' is broader — two processes are concurrent if their time windows overlap, even if they start and end at different instants; two court cases can run concurrently over a single month without ever happening on the same day. 'Asynchronous' is the contrast to all three: events are deliberately separated in time, each following its own rhythm rather than being tied to a shared schedule. In everyday examples, a synchronous online class meets at a fixed hour each week; an asynchronous course lets you watch the recordings on any day you choose.

simultaneous ↗synchronousconcurrent ↗

Common collocations

Nouns

Adverbs

  • fully asynchronous
  • completely asynchronous
  • partially asynchronous

Phrases

  • asynchronous vs synchronous
  • asynchronous transfer mode
  • asynchronous online learning

Etymology

GreekLatinEnglish

From Greek a- (not, without) + syn- (together) + chronos (time). The word entered English in the mid-1800s, first used in scientific contexts to describe events whose timing was not linked. By the late 1900s it became a standard term in computing for data transmission methods that do not rely on a shared clock.

First known use

1748

1748, in the meaning defined at sense 1