Definition of "bumpage"

BURNS: She has the sloping brow and cranial bumpage of the career criminal.SMITHERS: Uh, sir, phrenology was dismissed as quackery 160 years ago.

1995, "Mother Simpson" (episode), The Simpsons (TV series)

Four full days of bumpage — no sign of being caught. Blousy tops thanks to a shipment of maternity gear from Addison's shoots help hide my faux belly from the rest of the staff, who sadly, must think I've just put on the pounds.

2016, Meghann Foye, Meternity, page 60