diphenylhydantoin
- n an anticonvulsant drug (trade name Dilantin) used to treat epilepsy and that is not a sedative
diphtheria
- n acute contagious infection caused by the bacterium Corynebacterium diphtheriae; marked by the formation of a false membrane in the throat and other air passages causing difficulty in breathing
diphthong
- n a vowel sound that starts near the articulatory position for one vowel and moves toward the position for another