Wordnet 3.0
ADVERB (1)
1. 
 now and then or here and there; 
- Example: "he was arrogant and occasionally callous"- Example: "open areas are only occasionally interrupted by clumps of trees"- Example: "they visit New York on occasion"- Example: "now and again she would take her favorite book from the shelf and read to us"- Example: "as we drove along, the beautiful scenery now and then attracted his attention"[syn: occasionally, on occasion, once in a while, now and then, now and again, at times, from time to time]
WordNet (r) 3.0 (2006):
from time to time
    adv 1: 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: occasionally, on occasion, once in
           a while, now and then, now and again, at times,
           from time to time]