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

ゴミ集積場[gomishuusekijou] village garbage collection point
英字集合[eijishuugou] alphabetic character set
家集[kashuu] poet's poetical works
歌集[kashuu] anthology
画集[gashuu] book of paintings in print

会集[kaishuu] audience
解集合[kaishuugou] set of solutions
寄集め[yoseatsume] mish-mash
寄せ集める[yoseatsumeru] to put together
寄り集まる[yoriatsumaru] to gather together