to find someone or something by accident; to happen on someone or something. (Upon is formal and less commonly used than on.)I chanced upon a nice little restaurant on my walk today.I chanced on an old friend of yours in town today.
Also, chance upon. Happen upon, find or meet accidentally, as in In Paris we chanced on a wonderful little restaurant, or Andrew chanced upon his karate teacher in the health-food store. [Mid-1500s]
To find or meet someone or something accidentally; happen upon someone or something: While in Atlanta we chanced on two old friends. I chanced upon my neighbor while I was shopping at the mall.