We're looking into the history of our company and its founder and we've come across his listing in the University of Illinois College Catalog. We know that he graduated with his Bachelor's in Civil Engineering from Iowa State in 1905, which explains the first part of the listing. He also obtained his Civil Engineering license in 1911, but we aren't sure what the designation "do" meant in the following context:

LAST NAME First Name Middle Name (BCE (Ia St) '05 CE (do)'11)

Thank you!