Source : Webster's Revised Unabridged Dictionary (1913)

Significantly \Sig*nif"i*cant*ly\, adv.
   In a significant manner.

Source : WordNet®

significantly
     adv 1: in a statistically significant way; "the two groups differed
            significantly"
     2: in a significant manner; "our budget will be significantly
        affected by these new cuts" [ant: {insignificantly}]
     3: in an important way or to an important degree; "more
        importantly, Weber held that the manifold meaning attached
        to the event by the social scientist could alter his
        definition of the concrete event itself" [syn: {importantly}]