1. No longer in existence; lost or especially having died out leaving no living representatives
   - extinct 
2. No longer existing or inaccessible through loss or destruction
   "its nonextant original was written on vellum"

See also: dead, nonexistent

• atomic number 94
• atomic number 95
• atomic number 96
• atomic number 97
• atomic number 98
• atomic number 99
• atomic physics
• atomic pile
• atomic power
• atomic reactor
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• atomic theory
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• atomic weapon
• atomic weight
• atomically
• atomicity
• atomisation
• atomise
• atomiser
• atomism
• atomist
• atomist theory
• atomistic
• atomistic theory