grotto (n.)

early 15c., cripte, "grotto, cavern," from Latin crypta "vault, cavern," from Greek krypte "a vault, crypt" (short for krypte kamara "hidden vault"), fem. of kryptos "hidden," verbal adjective from kryptein "to hide," which is of uncertain origin. Comparison has been made to Old Church Slavonic kryjo, kryti "to hide," Lithuanian kráuti "to pile up." Beekes writes that krypto "is formally and semantically reminiscent of [kalypto]; the verbs may have influenced each other." For this, see calypto-. But he adds, "However, since there is no good IE etymology, the word could be Pre-Greek." Meaning "underground burial vault or chapel in a church" is attested by 1789.

short for grotto, c. 1500; perhaps from or influenced by French grotte.

"wildly formed, of irregular proportions, boldly odd," c. 1600s, originally a noun (1560s), from French crotesque (16c., Modern French grotesque), from Italian grottesco, literally "of a cave," from grotta (see grotto). The explanation that the word first was used of paintings found on the walls of Roman ruins revealed by excavation (Italian pittura grottesca) is "intrinsically plausible," according to OED. Originally merely fanciful and fantastic, the sense became pejorative, "clownishly absurd, uncouth," after mid-18c. As the British name for a style of square-cut, sans-serif letter, from 1875. Related: Grotesquely; grotesqueness.