captain's imperfect entry
• Centre international de l'enfance (French: International Children's Centre)
• Chem. collisional ionization equilibrium
• Commission Internationale de l'éclairage (French: International Commission on Illumination; ICI)
• Companion of the Order of the Indian Empire (former honour)
• Confédération internationale des étudiants (French: International Confederation of Students)
• (Ireland ) Córas Iompair Éireann (Irish Gaelic: Transport Organization of Ireland)