[1] : The Collaborative International Dictionary of English v.0.48

occasionally \occa"sionally\, adv.
   in an occasional manner; on occasion; at times, as
   convenience requires or opportunity offers; not regularly.
   --stewart.
   1913 webster

         the one, wolsey, directly his subject by birth; the
         other, his subject occasionally by his preferment.
                                                  --fuller.
   1913 webster

[2] : WordNet (r) 2.0

occasionally
     adv : now and then or here and there; "he was arrogant and
           occasionally callous"; "open areas are only
           occasionally interrupted by clumps of trees"; "they
           visit new york on occasion"; "now and again she would
           take her favorite book from the shelf and read to us";
           "as we drove along, the beautiful scenery now and then
           attracted his attention" syn: on occasion, once in
           a while, now and then, now and again, at times,
           from time to time
see also:
on occasion once in a while now and then now and again at times from time to time 

[3] : Moby Thesaurus II by Grady Ward, 1.0

38 moby thesaurus words for "occasionally":
   at infrequent intervals, at intervals, at odd times, at times,
   at various times, betweentimes, betweenwhiles, brokenly,
   by catches, by fits, by jerks, by skips, by snatches,
   disconnectedly, discontinuously, every so often, fitfully,
   haphazardly, here and there, in spots, infrequently,
   intermittently, irregularly, now and then, off and on,
   on divers occasions, on occasion, once and again,
   only occasionally, only when necessary, per saltum, periodically,
   randomly, skippingly, sometimes, sporadically, uncommonly,
   willy-nilly

Occasionally >> O Words
Occasionally, definition of term: Occasionally
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