primal

Adjective

• having existed from the beginning; in an earliest or original stage or state
  • aboriginal forests
    
  • primal eras before the appearance of life on earth
    
  • the forest primeval
    
  • primordial matter
    
  • primordial forms of life
    

• serving as an essential component
  • a cardinal rule
    
  • the central cause of the problem
    
  • an example that was fundamental to the argument
    
  • computers are fundamental to modern industrial structure
    

Related words

• Synonyms: 
  aboriginal , primeval , primaeval , primordial , cardinal , central , fundamental , key