1. 
[syn: synchronous, synchronal, synchronic]
The Collaborative International Dictionary of English v.0.48:
Synchronal \Syn"chro*nal\, a. [See Synchronous.]
   Happening at, or belonging to, the same time; synchronous;
   simultaneous. --Dr. H. More.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Synchronal \Syn"chro*nal\, n.
   A synchronal thing or event.
   [1913 Webster]
WordNet (r) 3.0 (2006):
synchronal
    adj 1: occurring or existing at the same time or having the same
           period or phase; "recovery was synchronous with therapy"-
           Jour.A.M.A.; "a synchronous set of clocks"; "the
           synchronous action of a bird's wings in flight";
           "synchronous oscillations" [syn: synchronous,
           synchronal, synchronic] [ant: asynchronous]