pro·tu·ber·ate 
(prō-tbə-rāt′, -ty-, prə-)
(prō-tbə-rāt′, -ty-, prə-)intr.v. pro·tu·ber·at·ed, pro·tu·ber·at·ing, pro·tu·ber·ates
To swell or bulge.
[Late Latin prōtūberāre, prōtūberāt- : Latin prō-, forth; see PRO-1 + Latin tūber, a swelling; see teuə- in the Appendix of Indo-European roots.]
pro·tu′ber·ation n.