Definition of "foliation"
foliation
/fəʊlɪˈeɪʃn/
noun
countable and uncountable, plural foliations
(geology) The property, possessed by some crystalline rocks, of being divided into plates or layers, due to the cleavage structure of one of the constituents, as mica or hornblende. It may sometimes include slaty structure or cleavage, though the latter is usually independent of any mineral constituent, and transverse to the bedding, it having been produced by pressure.