Collateral Duty Inspector, a maintenance position doing quality assurance

Conditioned Diphase, a form of diphase modulation

Coherent Diffraction Imaging, a lensless nanoscale imaging technique

Cranial diabetes insipidus, an endocrinological disorder

Christian Democrat International

CD-i, Compact Disc Interactive, interactive multimedia CD player and format developed and marketed by Royal Philips Electronics N.V.

Carbonyldiimidazole, a peptide coupling agent

Controlled Demolition, Inc., a major Building implosion contractor

The three letter acronym CDI may stand for:

Capacitor discharge ignition, an ignition system common for motorcycle engines

Churchill Downs Incorporated

Custodial Detention Index, a list of US residents compiled by FBI during 1939-1941, and later used for Japanese American internment.

Course deviation indicator, an aircraft navigation instrument

Chung Dahm Institute

Comisión Nacional para el Desarrollo de los Pueblos Indígenas, Mexico's National Commission for the Development of Indigenous Peoples

Collège des Ingénieurs, an educational institution in France and Germany

Customer data integration

Current density imaging, a medical imaging technique using magnetic resonance imaging (MRI)

Category Development Index is a measure used in the allocation of media, and promotion for a specific product category or genre

Center for Defense Information

Comitê para Democratização da Informática (committee for democratization of computer science)

Common Direct Injection, a synonym of common rail

Compass Directional Indicator, part of aircraft navigational equipment such as AHRS, EFIS, CTOT, Vertical & Horizontal Gyro

Cyrel Digital Imager, a direct laser engraving flexography plate printing device