di·et 1 (d???t)n.1. The usual food and drink of a person or animal.2. A regulated selection of foods, as for medical reasons or cosmetic weight loss.3. Something used, enjoyed, or provided regularly: subsisted on a diet of detective novels during his vacation.adj.1. Of or relating to a food regimen designed to promote weight loss in a person or an animal: the diet industry.2. a. Having fewer calories.b. Sweetened with a noncaloric sugar substitute.3. Designed to reduce or suppress the appetite: diet pills; diet drugs.v. di·et·ed, di·et·ing, di·ets v.intr. To eat and drink according to a regulated system, especially so as to lose weight or control a medical condition.v.tr. To regulate or prescribe food and drink for.[Middle English diete, from Old French, from Latin diaeta, way of living, diet, from Greek diaita, back-formation from diait?sthai, to live one’s life, middle voice of diait?n, to treat.]di?et·er n.di·et 2 (d???t)n.1. A national or local legislative assembly in certain countries, such as Japan.2. A formal general assembly of the princes or estates of the Holy Roman Empire.[Middle English diete, day’s journey, day for meeting, assembly, from Medieval Latin di?ta, alteration (influenced by Latin di?s, day) of Latin diaeta, daily routine; see diet1.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.diet (?da??t) n1. (Medicine) a. a specific allowance or selection of food, esp prescribed to control weight or in disorders in which certain foods are contraindicated: a salt-free diet; a 900-calorie diet. b. (as modifier): a diet bread. 2. (Cookery) the food and drink that a person or animal regularly consumes: a diet of nuts and water. 3. regular activities or occupationsvb (Cookery) (usually intr) to follow or cause to follow a dietary regimen[C13: from Old French diete, from Latin diaeta, from Greek diaita mode of living, from diaitan to direct one’s own life] ?dieter ndiet (?da??t) n1. (Government, Politics & Diplomacy) (sometimes capital) a legislative assembly in various countries, such as Japan2. (Government, Politics & Diplomacy) (sometimes capital) Also called: Reichstag the assembly of the estates of the Holy Roman Empire3. (Historical Terms) (sometimes capital) Also called: Reichstag the assembly of the estates of the Holy Roman Empire4. (Law) Scots law a. the date fixed by a court for hearing a caseb. a single session of a court[C15: from Medieval Latin di?ta public meeting, probably from Latin diaeta diet1 but associated with Latin di?s day]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014di?et1 (?da? ?t) n. 1. food and drink considered in terms of qualities, composition, and effects on health. 2. a particular selection of food, esp. for improving a person’s physical condition or to prevent or treat disease: a low-fat diet. 3. such a selection or a limitation on the amount a person eats for reducing weight: to go on a diet. 4. the foods habitually eaten by a particular person, animal, or group. 5. any?thing habitually provided or partaken of: a steady diet of game shows and soap operas. v.i. 6. to select or limit the food one eats, esp. to lose weight. 7. to eat according to the requirements of a diet. v.t. 8. to regulate or limit the food of. 9. to feed. adj. 10. suitable for consumption with a weight-reduction diet: diet soda. [1175?1225; diete