rocaille

[roh-kahy; French raw-kah-yuh] /roʊˈkaɪ; French rɔˈkɑ yə/
noun
1.
Fine Arts. any of the fantastic ornamental, often asymmetrical, combinations characteristic of the Rococo period, consisting of rock, shell, and plant forms combined with artificial forms, esp C -curves.
Origin
1855-60; < French: pebble-work, derivative of roc rock1
British Dictionary definitions for rocaille

rocaille

/rɒˈkaɪ/
noun
1.
decorative rock or shell work, esp as ornamentation in a rococo fountain, grotto, or interior
Word Origin
from French, from rocrock1