Bonanza (noun)

1. A sudden and unexpected source of wealth or good fortune.
2. A large and valuable discovery or gain.
3. A period of prosperity or success.
4. A sudden and substantial increase in business, trade or profits.
5. A situation that is greatly advantageous or profitable.

Origin:

The word 'bonanza' originated from the spanish word 'bonanza', which means 'a rich vein of ore'. it was first used to describe a rich vein of ore in a mine, and then extended to mean a sudden and unexpected source of wealth or good fortune.

Examples:

1. The company's stock has been a bonanza for investors.
2. The discovery of oil was a bonanza for the small town.
3. The country's economy has been experiencing a bonanza of growth.
4. The invention of the internet has been a bonanza for communication and commerce.
5. The sudden increase in tourism has been a bonanza for local businesses.