What does synchronous mean?
Synchronous describes things that happen at the same time or are carefully coordinated in their timing. A synchronous meeting allows participants in different locations to interact in real time, while synchronous communication means that messages or signals are handled in a coordinated sequence. The word is also used in computing, telecommunications, engineering, and biology to describe systems that operate in step or at matching times. Its contrast is asynchronous, which refers to activities that are not synchronized and may proceed independently. In everyday use, synchronous often conveys immediacy and coordination, though this can make it less suitable than concurrent or simultaneous in some contexts. The term is especially useful when timing itself is important: it distinguishes events or processes that are aligned with one another from those that merely happen to overlap.
Occurring at the same time or existing simultaneously.
"The two concerts were synchronous, beginning at exactly the same moment."
Use for events or activities that happen simultaneously, especially when exact timing or coordination matters.
Operating in step or coordinated in timing with another process, event, or system.
"The transmitter uses a synchronous protocol to keep the sending and receiving devices aligned."
This sense is especially common in computing, telecommunications, engineering, and biology.
In a synchronous world, everything happens at once; in an asynchronous one, timing becomes flexible.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does synchronous come from?
The word comes from Greek synchronos, meaning “at the same time” or “simultaneous.” It was formed from synchronos, related to Greek syn- (“together”) and chronos (“time”), the same broad time-related root found in words such as chronology and chronometer. English borrowed the term in the early modern period, and its modern technical meanings developed as it was applied to clocks, communications, computing, and coordinated biological processes.
Related word forms
How synchronous is actually used
Common in general writing for simultaneous activity, but especially frequent in computing, telecommunications, engineering, and biology. In technical contexts, it may distinguish precisely coordinated timing from processes that proceed independently.
Easily confused with synchronous
Synchronous events or processes occur at the same time, whereas asynchronous ones do not occur in exact timing with one another.