1. A native double salt, consisting of a combination of neutral and acid sodium carbonate, occurring as a white crystalline fibrous deposit from certain soda brine springs and lakes
   - trona

Encyclopedia: Urao

• projectile
• projecting
• projection
• projection screen
• projectionist
• projective device
• projective geometry
• projective technique
• projective test
• projector
• prokaryote
• prokaryotic
• Prokayotae
• Prokhorov
• Prokofiev
• prolactin
• prolamine
• prolapse
• prolapsus
• prolate
• prolate cycloid
• prole
• proleg
• prolegomenon
• prolepsis