No offense, but the Park tool literature called the tool used to check a chain for "wear / stretch", so maybe the terminology isn't so wrong. When Park changes their terminology, I will change mine.
I haven't checked the lock nut yet as the bike just went through a full servicing about 3 months ago and I don't see any side to side movement. I am still waiting for my lock nut tool to be delivered, so I didn't pop the wheel off yet.