Since at least the 18th century, grotesque has come to be used as a general adjective for the strange, mysterious, magnificent, fantastic, hideous, ugly, incongruous, unpleasant, or disgusting, and thus is often used to describe weird shapes and distorted forms such as Halloween masks. In art, performance, and literature, however, grotesque may also refer to something that simultaneously invokes an audience feeling of uncomfortable bizarreness as well as sympathetic pity.

A grotto is a natural or artificial cave used by humans in both modern times and antiquity, and historically or prehistorically. Naturally occurring grottoes are often small caves near water that are usually flooded or often flooded at high tide. Sometimes, artificial grottoes are used as garden features. The Grotta Azzurra at Capri and the grotto at Tiberius' Villa Jovis in the Bay of Naples are examples of popular natural seashore grottoes.