grotto

Noun

grotto (plural grottos or grottoes)

1. A small cave.
2. An artificial cavern-like retreat.
   • ...But, while we are waiting for the temple, can you not show us the altar?—we want to see your grotto."
     Pope desired nothing better than to show his new toy, and led the way to the pretty and fanciful cave, which was but just finished.1837, L[etitia] E[lizabeth] L[andon], “Pope’s Villa”, in Ethel Churchill: Or, The Two Brides. […], volume I, London: Henry Colburn, […], →OCLC, page 192
3. A Marian shrine, usually built in a cavern-like structure.
4. A local organization of cavers that typically organizes trips to caves and provides information and training for caving; a caving club.
   • An earlier attempt to organize a grotto in the Indiana, PA, area in the mid-1970s failed to succeed, but from it developed the informal Chestnut Ridge Explorers Association.1987, National Speleological Society, NSS News, volumes 45-46, page 331
   • By the mid-1940s members of local grottos (regional clubs of cavers within the National Speleological Society) were exploring Porcupine Cave (Bloch, 1946).2004, Anthony D. Barnosky, Biodiversity Response to Climate Change in the Middle Pleistocene: The Porcupine Cave Fauna from Colorado
5. A secretive name for a local group of underground Satanists.
6. (Philippines) A garden or roadside shrine with a small cave containing a statue of the Blessed Virgin Mary (usually Our Lady of Lourdes and sometimes paired with a water feature)