Hit upon and Run across

Hit upon verb - To come upon unexpectedly or by chance.

Run across and hit upon are semantically related in happen upon topic. In some cases you can use "Run across" instead a verb "Hit upon", when it comes to topics like lay hands on.

Run across verb - Come together.

Hit upon and run across are semantically related in happen upon topic. Sometimes you can use "Hit upon" instead a verb "Run across", if it concerns topics such as lay hands on.