1. A dietetist.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• dietrician,
• dietitican,
• diatition,
• petitian,
• dietetians,
• dietition,
• diatitians,
• dietacian,
• dietetian,
• dieitian,
• deititian,
• dietitician,
• dietetican,
• dieticion,
• dietcian,
• dietican,
• dietian,
• dietitan,
• dietatian,
• diatician

The adjective form of the word "dietitian" is "dietetic".

The plural of the "dietitian" can be the "dietitians".

The singular of the "dietitian" can be the "dietitian".