1 a: to fall into sin or waywardness b: to make an error : blunder c: to come to an obstacle to belief
2: to trip in walking or running
3 a: to walk unsteadily or clumsily b: to speak or act in a hesitant or faltering manner
4 a: to come unexpectedly or by chance
I prefer the definition: being led on an unexpected trip to interesting and obscure sites that you would never visit on your own.
Think of Stumble as your own private, slightly wacky tour guide to the web. It was easy to log in to and even easier to navigate. I can see this becoming a very addictive pastime!