leucon Syllabification: (leu·con)Pronunciation: /ˈlo͞oˌkän/Definition of leucon noun Zoology a sponge of the most complex structure, composed of a mass of flagellated chambers and water canals. Compare with ascon and sycon.Derivatives leuconoidPronunciation: /-kəˌnoid/ adjective leucon in other Oxford dictionaries Definition of leucon in the British & World English dictionary