[rɔ'kai,rɔ'kɑ:j]
n.
花园石贝装饰物, 状似贝壳的装饰

Rocaille \Ro`caille"\, n. [F. Cf. {Rock} a stone.] (Art)
(a) Artificial rockwork made of rough stones and cement, as
for gardens.
(b) The rococo system of scroll ornament, based in part on
the forms of shells and water-worn rocks.
[Webster 1913 Suppl.]