Please exhale deeply.
This Tofu & Fugu pizza chain is expanding its franchise in a big way.
The value of yen has risen greatly.
This is the adverb version of the kanji big It's a little thing you can put in front of things to say that they are "in a big way" or "on a grand scale."
Since you already know the reading of the vocab word 大きい, you should be able to read this word as well.