1. Of or relating to the philosophical study of causation
   - etiological [N. Amer], etiologic [N. Amer], aetiological [Brit, Cdn] 
2. Relating to the aetiology of a disease
   - etiological [N. Amer], etiologic [N. Amer], aetiological [Brit, Cdn]

See also: aetiology [Brit, Cdn]

• investment firm
• investment funds
• investment letter
• investment trust
• investor
• investors club
• inveteracy
• inveterate
• inviable
• invidia
• invidious
• invidiously
• invidiousness
• invigilate
• invigilation
• invigilator
• invigorate
• invigorated
• invigorating
• invigoration
• invigorator
• invincibility
• invincible
• Invincible Armada
• invincibly