The DICT Development Group

  Asynchronous \A*syn"chro*nous\, a. [Gr. ? not + synchronous.]
     Not simultaneous; not concurrent in time; -- opposed to
     synchronous.
  
     Syn: nonsynchronous, unsynchronized, unsynchronous.
          [Webster 1913 Suppl.]
  
     2. (Paleontology) occurring in different geologic times; --
        of taxa/ synchronous
  
     Syn: allochronic
          [WordNet 1.5 +PJC]
  
     3. chronologically misplaced; belonging to a different time
        or era
  
     Syn: anachronic, anachronous, anachronistic
          [WordNet 1.5 +PJC]
  
     4. (Computers) occurring at different speeds in different
        computers connected by a data transmission link; -- said
        of methods data of transmission between computers.
        Opposite of synchronous.
        [PJC]

  asynchronous
      adj 1: (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 [ant:
             synchronous]
      2: not synchronous; not occurring or existing at the same time
         or having the same period or phase [ant: synchronal,
         synchronic, synchronous]

  asynchronous
  
      Not synchronised by a shared signal such as
     clock or semaphore, proceeding independently.
  
     Opposite: synchronous.
  
     1.  A process in a multitasking system
     whose execution can proceed independently, "in the
     background".  Other processes may be started before the
     asynchronous process has finished.
  
     2.  A communications system in which data
     transmission may start at any time and is indicated by a
     start bit, e.g. EIA-232.  A data byte (or other element
     defined by the protocol) ends with a stop bit.  A
     continuous marking condition (identical to stop bits but not
     quantized in time), is then maintained until data resumes.
  
     (1995-12-08)