dietitian/daɪəˈtɪʃən/EtymologyIrregular spelling of diet + -ician, probably influenced by dietetic.dietitian means A person who studies or practices dietetics. Lexicurio rates it Rare gem — a strength score of 78 out of 100.nounA person who studies or practices dietetics.“The dietitian works with the client to develop meal planning that meets the client's needs based on healthy food choices.”