Source : Webster's Revised Unabridged Dictionary (1913)

Schist \Schist\ (sh[i^]st), n. [Gr. ? divided, divisible, fr. ?
   to divide: cf. F. schiste. See {Schism}.] (Geol.)
   Any crystalline rock having a foliated structure (see
   {Foliation}) and hence admitting of ready division into slabs
   or slates. The common kinds are mica schist, and hornblendic
   schist, consisting chiefly of quartz with mica or hornblende
   and often feldspar.

Source : WordNet®

schist
     n : any metamorphic rock that can be split into thin layers