noun
large hole; big opening
Literal physical hole or gap, often implying something is missing or damaged.
道路に大穴が開いて通行止めになった。
A large hole opened up in the road and it was closed to traffic.
今年度の予算には大穴が空いている。
There is a huge deficit in this year's budget.
noun
long-shot win; big winnings; a killing
Used in horse racing and other betting to describe an unexpected victory by an outsider, or the large payout from such a bet.
競馬で大穴を当てて、大金を手にした。
I hit a long-shot win at the horse races and got a lot of money.