Home › Words › H › histiocytomahistiocytomahistiocytoma · noun — A tumour consisting of histiocytes.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom histiocyte + -oma = histio- + -cyte + -oma.nounA tumour consisting of histiocytes.Definitions & examples from Wiktionary (CC BY-SA 3.0).