sobre- 81
over- (from the lat. super- )
1 Prefix that expresses increase or reinforcement, superior position or the time that happens to the thing expressed by the name: overproduction, bonus, childbirth, after-dinner . As you can see in the 12th Accept. of on , with the last meaning is also written separately.
2 In front of a verb, in expressions that are already unused, express lightly or above : Sobrebarrer .