Learner's definition of SIGNIFICANTLY
1 : in a way that is large or important enough to be noticed or have an effect
People who smoke have a significantly greater risk of developing lung cancer than people who don't.
Another store sold the game for a significantly lower price.
If you take my advice, your chances of winning will increase/improve significantly.
2 [more significantly; most significantly] — used to say that something is important or meaningful
Significantly, William broke with family tradition and decided not to name his newborn son “William.”
It was the first time I had ever traveled outside of the country, but, more significantly, it was the first time I had ever been outside of my parents' supervision.
3 : in a way that has a special or hidden meaning