triennium/trieʹeni·əm/ noun (pl trienniums triennia /-ni·ə/)

• economy class
• economy-class syndrome
• economy of scale
• economy-size
• ecospecies
• ecosphere
• ecossaise
• ecosystem
• ecoterrorist
• ecotourism
• ecotype
• ecovillage
• eco-warrior
• ecru
• ECSC
• Ecstasy
• ecstasy
• ecstatic
• ECT
• ect-
• ectoblast
• ectoderm
• ectogenic
• ectogenous
• ectomorph