The three-letter acronym CDI may stand for: People Collateral Duty Inspector, a maintenance position doing quality assurance Science and technology Carbonyldiimidazole, a peptide coupling agent Coherent Diffraction Imaging, a lensless nanoscale imaging technique Collège des Ingénieurs, an educational institution in France and Germany Conditioned Diphase, a form of diphase modulation Automotive Capacitor discharge ignition, an ignition system common for motorcycle engines Comm… (More on Cdi)