bonanza
1. [ noun ] (geology) an especially rich vein of precious ore
Related terms: vein
2. [ noun ] a sudden happening that brings good fortune (as a sudden opportunity to make money)
Synonyms: goldmine manna_from_heaven bunce godsend gold_rush gravy windfall boom
Examples:

"the demand for testing has created a boom for those unregulated laboratories where boxes of specimen jars are processed like an assembly line"

Related terms: happening
Similar spelling:   Boening