Definition of "protuberate"
verb
third-person singular simple present protuberates, present participle protuberating, simple past and past participle protuberated
(intransitive) To bulge outward, producing a rounded protuberance.
Quotations
With respect to measurement, it would be advisable to take the circumference of the foot by placing the beginning of an inch tape measure a little beyond the great toenail, as the second toe is naturally the longest, passing the measure round the protuberating part of the heel, and bringing it up to the point of the beginning of the measure at the toe.
1844, Henry O'Shaughnessy, “Modern Shoemaking”, in The Mechanic's Magazine, Museum, Register, Journal and Gazette, volume 40, number 1067, page 42