It looks like rabbit or woodchuck except for the even cut along the veins, (especially along the top of the leaf) unless the leaf readily tears along the vein when chomped on and pulled by a creature.

It looks like chomp and tear damage which would explain the even damage along the veins. A box turtle would leave clean cuts like that but I am sure it isn't. I still don't believe turtles like hosta leaves.

My guess would be something with sharp incisors but not cuspids and bi-cuspids. I think a deer doesn't even have cuspids and bi-cuspids. Since rabbits are in the deer family, it could be rabbits, which usually snip with incisors and chew with molars to grind food, and go more for unfurled leaves. Did you ever see a deer eat an ear of feed corn?

It picks it up with its incisors and throws it up in the air, and catches it with head turned upward. The ear falls to the back of the mouth and it grinds the kernals off the cob which fall down into it's gullet.

Les

Our rabbits do not leave marks like that.
I don't know what it is, but I'm pretty certain it's not a rabbit, and certainly too large scale damage to be a bug!

Roof, roof.

Maybe a caterpillar of some sort? I found a few leaves that looked like that last year and there were 3-4 caterpillars doing a job on a single leaf....

Alexa