light on


Also, light upon. Happen upon, come across, discover. For example, John was delighted to light on a new solution to the problem, or We were following the path when suddenly we lit upon a cave. [Second half of 1400s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.