1. (biology) a hypothesis of directed evolution (as opposed to natural selection of random variations)

Encyclopedia: Orthogenesis

• prancer
• prandial
• prang
• prang up
• prank
• prankish
• prankishness
• prankster
• prase
• praseodymium
• prat
• prate
• prater
• pratfall
• pratincole
• pratique
• prattle
• prattler
• prau
• Praunus
• Pravachol
• pravastatin
• prawn
• prawn cocktail
• praxis