The word campus comes from the Latin word campus (a plain, open field) that derives from the Greek word campos (from campe) [bend, turn(ing), curve]. It was used in Sicily to describe a plain, level place, an expanse surrounded by woods, higher ground, etc. from the notion of the circus or riding-course, the act of bending or turning round horses. First used in college sense at Princeton.
From the same root: camp, camper, campaign, campaigner.
In modern Greek:
a) campos: an open field, a level place, a valley
b) campe: bend, curve
c) campyle: curve, curved line
a) campto: to bend, curve
b) camptome: to give in, relent
campe --> campos --> campus / camp
See the blog: English Words of no Apparent Greek Origin at http://ewonago.blogspot.com/