- a rich mass of ore, as found in mining.
- a source of great and sudden wealth or luck; a spectacular windfall: The play proved to be a bonanza for its lucky backers.
- a source, usually sudden and unexpected, of luck or wealth
- US and Canadian a mine or vein rich in ore
1844, American English, from Spanish bonanza “a rich lode,” originally “fair weather at sea, prosperity,” from Vulgar Latin *bonacia, from Latin bonus “good” (see bene-).