1. Of sound waves with frequency greater than 1000 million hertz 
2. Moving at more than five times the speed of sound

Encyclopedia: Hypersonic

• endoskeleton
• endosperm
• endospore
• endospore-forming bacteria
• endosteum
• endothelial
• endothelial myeloma
• endothelium
• endothermal
• endothermic
• endothermic reaction
• endotoxin
• endotracheal tube
• endovenous
• endow
• endowed
• endowment
• endowment fund
• endowment insurance
• endozoan
• endozoic
• endpaper
• endplate
• endpoint
• endue