This Find the 25 Design Terms game from Colle+McVoy was driving me bonkers last week because I could only find 24 terms. I came back to it this week, and the same deal. Grr!
I finally gave up and Googled it this morning. Someone on a user forum somewhere shared this tip: There are three terms hidden on the boy, and the term I could never find (#23) was one of them.
I tried again, and discovered that the reason I never found the third term on the boy was because I'd never heard of this word being used as a design term before, so it never occurred to me to click on that portion of him to see if it lights up. (Dirty!)
Admittedly, I learned most of my design terms in journalism school as opposed to art school, but still.
Anyhow, if you've got some time to kill and think you know your graphic design lingo, give it a try.