gametangiumEnglishOxford New American Dictionarygametangium /ˌɡaməˈtanjēəm, ˌɡæməˈtændʒiəm / ▸ noun (plural gametangia /-jēə/) Botany a specialized organ or cell in which gametes are formed in algae, ferns, and some other plants. – ORIGIN late 19th century : from modern Latin gameta (see gamete) + Greek angeion ‘vessel’ + -ium.