paramoudra
/ˌparəˈmuːdrə/Geology
noun
A large flint, sometimes 3 ft. (1 metre) long and 1 ft. (30 cms) thick, pear-shaped, barrel-shaped, or cylindrical and often with a central cavity, found (typically upright) in chalk strata, especially in north-east Ireland and Norfolk.
Origin
Early 19th century. Probably from Irish peura muireach/ˈpɛrə ˈmurjəx/, lit. ‘sea pears’ from Irish regional (Ulster) peura, plural form of peur + muireach of the sea, after their shape and their occurrence on the beach below chalk cliffs. The present form of the English word is probably influenced by para- and perhaps French moudre to grind.