Clays meaning : A mineral substance made up of small crystals of silica and alumina, that is ductile when moist; the material of pre-fired ceramics. An earth material with ductile qualities. A tennis court surface made of crushed stone, brick, shale, or other unbound mineral aggregate. The material of the human body. A particle less than 3.9 microns in diameter, following the Wentworth scale. A clay pipe for smoking tobacco. A clay pigeon. Land or territory of a country or other political region, especially when subject to territorial claims To add clay to, to spread clay onto. (of sugar) To purify using clay.