OCCASIONALLY

occasionally, on occasion, once in a while, now and then, now and again, at times, from time to time

(adverb) sporadically and infrequently; “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”

Source: WordNet® 3.1

Etymology

Adverb

occasionally (comparative more occasionally, superlative most occasionally)

(obsolete) On the occasion of something else happening; incidentally, by the way. [15th–18th c.]

From time to time; sometimes; at relatively infrequent intervals. [from 15th c.]

Synonyms: now and then, once in a while

(obsolete) By chance; accidentally. [17th–18th c.]

Synonyms

• on occasion, sometimes, at times, now and then

Source: Wiktionary

Oc*ca"sion*al*ly, adv.

Definition: In an occasional manner; on occasion; at times, as convenience requires or opportunity offers; not regularly. Stewart. The one, Wolsey, directly his subject by birth; the other, his subject occasionally by his preferment. Fuller.

OCCASIONAL

Oc*ca"sion*al, a. Etym: [Cf.F. occasionnel.]

1. Of or pertaining to an occasion or to occasions; occuring at times, but not constant, regular, or systematic; made or happening as opportunity requires or admits; casual; incidental; as, occasional remarks, or efforts. The... occasional writing of the present times. Bagehot.

2. Produced by accident; as, the occasional origin of a thing. [Obs.] Sir T. Browne. Occasional cause (Metaph.), some circumstance preceding an effect which, without being the real cause, becomes the occasion of the action of the efficient cause; thus, the act of touching gunpowder with fire is the occasional, but not the efficient, cause of an explosion.

Source: Webster’s Unabridged Dictionary 1913 Edition