1 [mass noun] an 18th-century artistic or architectural style of decoration characterized by elaborate ornamentation with pebbles and shells, typical of grottos and fountains:a room with walls in rocaille like those of fountains in a park [as modifier]:heavy frames of gilt rocaille stucco-work
2a tiny ornamental bead:rocailles are available in a range of opaque colours
French, from roc 'rock'
rocaille in other Oxford dictionaries
Definition of rocaille in the US English dictionary