Large
Substantial, Drastic, Major
noun, な adjective
Something big in width is large. In fact, it's of a pretty substantial size. This word is used to describe a large magnitude or degree of change, increase, decrease, or difference in a given situation.
The readings for this word are both kun'yomi readings. You've learned both of these readings by now so you should be able to read this on your own.
大幅なコストダウン
a substantial cost reduction
大幅な変更
a substantial change
大幅な減少
a substantial decrease
大幅な増加
a substantial increase
大幅に改善する
to improve substantially, to make extensive improvements
大幅に上回る
to exceed substantially
大幅に減少する
to decrease substantially
大幅に増加する
to increase substantially
会議の資料が大幅に変更されました。
The meeting’s documents were substantially altered.
干ばつの影響で野菜が大幅に値上がりした。
The price of vegetables has gone up substantially due to the drought.
インフルエンザワクチンの開発は、死亡者数の大幅な減少をもたらしました。
The development of flu vaccines led to a drastic decrease in the number of deaths.