I. bum·per ˈbəm-pər noun
Etymology: probably from bump to bulge
Date: 1676
1. : a brimming cup or glass
2. : something unusually large
II. bumper adjective
Date: 1885
1. : unusually large
a bumper crop
2. : banner 2
III. bump·er ˈbəm-pər noun
Date: 1839
1. : a device for absorbing shock or preventing damage (as in collision) ; specifically : a bar at either end of an automobile
2. : one that bumps
3. : a brief interval on radio or television filled with music, video shots, or voiceovers that marks a break between a program and a commercial