Significantly means to an extent that really matters. Significantly higher, significantly improved, paused significantly.
It has two lives: in ordinary writing it means by a lot, and in statistics it means unlikely to be chance, which need not be large at all. That gap is where a great many misreported findings come from.
1adverbsignificantlyTo an extent that really matters.
“Prices have gone up significantly since last year.”
significantly is a manner.
From significant + -ly.
Etymology from Wiktionary, CC BY-SA