'Sardonyx' definitions:

Definition of 'sardonyx'

From: WordNet
noun
An onyx characterized by parallel layers of sard and a different colored mineral

Definition of 'Sardonyx'

From: GCIDE
  • Sardonyx \Sar"do*nyx\, n. [L., fr. Gr. ?. See Sard, and Onyx.] (Min.) A variety of onyx consisting of sard and white chalcedony in alternate layers. [1913 Webster]

Definition of 'Sardonyx'

From: Easton
  • Sardonyx (Rev. 21:20), a species of the carnelian combining the sard and the onyx, having three layers of opaque spots or stripes on a transparent red basis. Like the sardine, it is a variety of the chalcedony.