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  1. food and drink considered in terms of its qualities, composition, and its effects on health: Milk is a wholesome article of diet.
  2. a particular selection of food, especially as designed or prescribed to improve a person's physical condition or to prevent or treat a disease: a diet low in sugar.
  3. such a selection or a limitation on the amount a person eats for reducing weight: No pie for me, I'm on a diet.
  4. the foods eaten, as by a particular person or group: The native diet consists of fish and fruit.
  5. food or feed habitually eaten or provided: The rabbits were fed a diet of carrots and lettuce.
  6. anything that is habitually provided or partaken of: Television has given us a steady diet of game shows and soap operas.
verb (used with object), di·et·ed, di·et·ing.
  1. to regulate the food of, especially in order to improve the physical condition.
  2. to feed.
verb (used without object), di·et·ed, di·et·ing.
  1. to select or limit the food one eats to improve one's physical condition or to lose weight: I've dieted all month and lost only one pound.
  2. to eat or feed according to the requirements of a diet.
  1. suitable for consumption with a weight-reduction diet; dietetic: diet soft drinks.

Origin of diet

1175–1225; (noun) Middle English diete < Anglo-French, Old French < Latin diaeta < Greek díaita way of living, diet, equivalent to dia- dia- + -aita (akin to aîsa share, lot); (v.) Middle English dieten (transitive) < Anglo-French, Old French dieter, derivative of the noun
Related formsdi·et·er, nounnon·di·et·er, nounnon·di·et·ing, adjective, noun


  1. the legislative body of certain countries, as Japan.
  2. the general assembly of the estates of the former Holy Roman Empire.

Origin of diet

1400–50; late Middle English < Medieval Latin diēta public assembly, apparently the same word as Latin diaeta (see diet1) with sense affected by Latin diēs day Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for diet

Contemporary Examples of diet

Historical Examples of diet

British Dictionary definitions for diet


    1. a specific allowance or selection of food, esp prescribed to control weight or in disorders in which certain foods are contraindicateda salt-free diet; a 900-calorie diet
    2. (as modifier)a diet bread
  1. the food and drink that a person or animal regularly consumesa diet of nuts and water
  2. regular activities or occupations
  1. (usually intr) to follow or cause to follow a dietary regimen
Derived Formsdieter, noun

Word Origin for diet

C13: from Old French diete, from Latin diaeta, from Greek diaita mode of living, from diaitan to direct one's own life


  1. (sometimes capital) a legislative assembly in various countries, such as Japan
  2. Also called: Reichstag (sometimes capital) the assembly of the estates of the Holy Roman Empire
  3. Scots law
    1. the date fixed by a court for hearing a case
    2. a single session of a court

Word Origin for diet

C15: from Medieval Latin diēta public meeting, probably from Latin diaeta diet 1 but associated with Latin diēs day
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for diet

"regular food," early 13c., from Old French diete (13c.) "diet, pittance, fare," from Medieval Latin dieta "parliamentary assembly," also "a day's work, diet, daily food allowance," from Latin diaeta "prescribed way of life," from Greek diaita, originally "way of life, regimen, dwelling," related to diaitasthai "lead one's life," and from diaitan, originally "separate, select" (food and drink), frequentative of *diainysthai "take apart," from dia- "apart" + ainysthai "take," from PIE root *ai- "to give, allot." Often with a sense of restriction since 14c.; hence put (someone) on a diet (mid-15c.).


"assembly," mid-15c., from Medieval Latin dieta, variant of diaeta "daily office (of the Church), daily duty, assembly, meeting of counselors," from Greek diaita (see diet (n.1)), but associated with Latin dies "day" (see diurnal).


late 14c., "to regulate one's diet for the sake of health," from Old French dieter, from diete (see diet (n.1)); meaning "to regulate oneself as to food" (especially against fatness) is from 1650s. Related: Dieted; dieting. An obsolete word for this is banting. The adjective in this sense (Diet Coke, etc.) is from 1963, originally American English.

Online Etymology Dictionary, © 2010 Douglas Harper

diet in Medicine


  1. Food and drink in general.
  2. A prescribed course of eating and drinking in which the amount and kind of food, as well as the times at which it is to be taken, are regulated for therapeutic purposes.
  3. Reduction of caloric intake so as to lose weight.
  1. To eat and drink according to a regulated system, especially so as to lose weight or control a medical condition.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.