Ve ‧ su ‧ vi ‧ us /vəˈsuːviəs, vɪˈsuːviəs/ BrE AmE ( also Mount Vesuvius )
a ↑ volcano (=a mountain with a large hole at the top) in southeast Italy. When Vesuvius erupted (↑ erupt ) in AD 79, sending out ↑ ash and ↑ lava (=hot liquid rock) , it buried the ancient Roman city of Pompeii. Vesuvius is still an ‘active’ volcano, which could erupt again at any time.