| CAS-REGN | Chemical Abstracts Service Registry Number |
|---|---|
| CT | calcitonin; calf testis; cardiac tamponade; cardiothoracic [ratio]; carotid tracing; carpal tunnel; ... |
| CTN | calcitonin; clinical trials notification; computer tomography number; continuous noise |
| DN | Deiter's nucleus; dextrose-nitrogen; diabetic neuropathy; dibucaine number; dicrotic notch; dinitroc... |
| ECN | equipment control number |