Lumps of clay is a term used to describe small, irregularly shaped pieces of clay. FISTS is an acronym for 'Fired In Situ Thermal System', which is a method of firing clay in its original location. CLODS is an acronym for 'Compacted Lumps Of Dry Soil', which is a type of soil that has been compacted into lumps. Both FISTS and CLODS are related to lumps of clay, as they both involve the manipulation of clay in some way.