Simple past tense and past participle of chance.(verb)
Discovered by chance.(adjective)
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Use "chanced" in a sentence
"J.R.R. Tolkien, on the other hand, was so very much a man of letters that he did not even attempt to publish any of his fiction until a reader at Allen and Unwin chanced to hear of The Hobbit and pried the typescript out of his hands."
"At home during the winter holidays, his name chanced to cross her lips."
"'Clara,' or 'Kate,' as the name chanced to be, 'this is the gentleman who saved me from the dog.'"