1. One billionth 10^(-9); more generally, very small

Encyclopedia: Nano-

• Callitris quadrivalvis
• Callophis
• Callorhinus
• Callorhinus ursinus
• callosectomy
• callosity
• callosotomy
• callous
• calloused
• callously
• callousness
• callow
• callowness
• callsign
• Calluna
• Calluna vulgaris
• callus
• calm
• calm air
• calm down
• calming
• calmly
• calmness
• Calnada pea
• Calocarpum