pro ‧ tu ‧ be ‧ rance /prəˈtjuːb ə rənt $ -ˈtuː-/ BrE AmE noun [countable]
[ Date: 1600-1700 ; Origin: protuberant , from Latin , present participle of protuberare , from tuber 'swelling' ]
formal something that sticks out:
This dinosaur is recognizable by the protuberance on the top of its head.
—protuberant adjective