“Yale Grad” Three letters. Answer:Eli. 
“Elis” is a nickname for Yalies, named after Elihu Yale.
…just sayin’ …
You could have answered your question yourself by looking up Eli in Wikipedia, or Yale, or by Googling “college nicknames,” or any number of other routes.
On older TV shows you can hear people talking about “Son of old Eli” and when I was little that confused me a lot