ひと塊[ikkai] one lump
塊根[kaikon] tuberous root
塊状[kaijou] massive
凝塊[gyoukai] clot
金塊[kinkai] nugget

集塊[shuukai] agglomerate (e.g. of cells, molecules, etc.)
団塊の世代[dankainosedai] baby boom generation
土塊[dokai] lump of earth
肉塊[nikukai] piece of meat
氷塊[hyoukai] lump of ice