asynchronous

/eɪˈsɪŋkrənəs/

Events are asynchronous when they don't happen at the same time. If you pick up the crossword puzzle I started yesterday, we are working on it together but in an asynchronous fashion. Please do it in pencil.

Asynchronous is the opposite of synchronous, which means happening at the same time. Think of “synchronous” as “in synch” and asynchronous as “out of synch.” If we're chatting on the phone, our communication is “synchronous.” We respond to each other immediately and when we hang up, the conversation's over. Email is asynchronous because we respond whenever it's convenient. In some cases this means never, which can be mighty convenient.

Definitions of asynchronous

1. adjective

   not synchronous; not occurring or existing at the same time or having the same period or phase
   synonyms:

   allochronic

   (of taxa) occurring in different geologic times

   anachronic, anachronistic, anachronous

   chronologically misplaced

   nonsynchronous, unsynchronised, unsynchronized, unsynchronous

   not occurring together

   in series, nonparallel, serial

   of or relating to the sequential performance of multiple operations

   antonyms:

   synchronous

   occurring or existing at the same time or having the same period or phase

   synchronic

   concerned with phenomena (especially language) at a particular period without considering historical antecedents

   coetaneous, coeval, contemporaneous

   of the same period

   coexistent, coexisting

   existing at the same time

   co-occurrent, coincident, coincidental, coinciding, concurrent, cooccurring, simultaneous

   occurring or operating at the same time

   contemporaneous, contemporary

   occurring in the same period of time

   parallel

   of or relating to the simultaneous performance of multiple operations

   synchronic

   (of taxa) occurring in the same period of geological time

   synchronised, synchronized

   operating in unison
2. adjective

   (digital communication) pertaining to a transmission technique that does not require a common clock between the communicating devices; timing signals are derived from special characters in the data stream itself
   antonyms:

   synchronous

   (digital communication) pertaining to a transmission technique that requires a common clock signal (a timing reference) between the communicating devices in order to coordinate their transmissions