- a volcanic rock in which rounded cavities formed by the expansion of gas or steam have later become filled with deposits of various minerals.
adjective Also a·myg·da·loi·dal.
- (of rocks) containing amygdules.
- Anatomy. of or relating to an amygdala.
- a volcanic igneous rock containing amygdales
- having the shape of an almond
- a less common form of amygdaloidal (def. 1)
- Shaped like an almond.
- Of or relating to an amygdala.