fortuitous

fortuitous    [fawr-Too-i-tuh s]

adjective.  occurring by lucky chance

"A rock falling on your head is an accident, dollar bills falling on your head is fortuitous."
"Other states like North Dakota have benefited from the fortuitous exploitation of abundant raw materials, primarily oil and gas."
"Since taking the CEO job over two years ago, Marissa Mayer has coasted on Yahoo's fortuitous early investment of Alibama."

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