Aclastic rock is named according to what ?

Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,[1] chunks and smaller grains of rock broken off other rocks by physical weathering.[2] Geologists use the term clastic with reference to sedimentary rocks as well as to particles in sediment transport whether in suspension or as bed load, and in sediment deposits.