<p><strong>Noun</strong></p><ul><li>food and drink considered in terms of its qualities, composition, and its effects on health: The ad shows milk and dairy as a wholesome part of our daily diet.</li><li>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 is often recommended for diabetes prevention.</li><li>a selection of food that emphasizes caloric restriction or otherwise limits the amount a person eats, usually intended to induce weight loss: No pie for me, I'm on a diet.</li><li>the foods eaten, as by a particular person or group: The Mediterranean diet consists historically of fish, fruit, vegetables, whole grains, and nuts.</li><li>food or feed habitually eaten or provided: The rabbits were fed a diet of carrots and lettuce.</li><li>anything that is habitually provided or partaken of: Television has given us a steady diet of reality shows and police procedurals.</li></ul><p><strong>Adjective</strong></p><ul><li>suitable for consumption as part of a selection of food intended to induce weight loss: I usually drink diet soft drinks.</li><li>formulated to be lower in calories, fat, sugar, etc. than a similar food: The diet version of the cookie does taste different.</li></ul><p><strong>Verb</strong> (used without object)</p><ul><li>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.</li><li>to eat or feed according to the requirements of a particular or prescribed selection of food.</li></ul><p><strong>Verb</strong> (used with object)</p><ul><li>to regulate the food of, especially in order to improve the physical condition: They dieted the dog to a healthy weight of 20 pounds.</li></ul>