From Longman Dictionary of Contemporary Englishrun across somebody/something phrasal verbMEETto meet someone or find something by chance I ran across him at a conference in Milan. I ran across some old love letters while I was clearing out a cupboard. → run→ See Verb table
Examples from the Corpus
run across • Dorigo ran down inside left 30-40 yards unchallenged, hit a through ball which Wallace ran across from right centre on to.• A pretty smile ran across her face as she listened to his answer.• Fat screaming women ran across the boulevard to get in line for the quiz shows.• I run across the car park.• The Plot Once upon a time a mouse ran across the paw of a sleeping lion.• I ran across the road and jumped up, clinging to the side of the phaeton.• A shell exploded just in front of me, and just over a woman as she ran across the street.• The border line between the two states runs across the summit of Elbrus. 