Chock-full (also chock full or chockfull) is a term meaning that something is full to the brim, loaded, as full as something can get.
According to Merriam Webster, it’s from the Middle English word chokkeful with a first use in the 1500s. It may relate to the word “choke” referring to the cheek (cheekful? hmmm…).
My first guess would have been that a “chock” was some sort of medieval container. Not so.
What else comes to mind is Chock Full O’Nuts, which I always thought was a funny name for a coffee brand as coffee’s not exactly made with nuts. Interestingly, I looked that up on the company website and found that its founder, William Black did own a bunch of nut shops. So I guess the name just stuck!
Note that chalk and chock are homonyms and I’ve seen someone use the term “chalked full” by accident as I mention in this post. Don’t do that.