Every living organism needs some substances that are essential for it to survive and which cannot be manufactured in the organism's body. These substances are used as sources of energy, for all the chemical reactions that go on in the body and for the development of the basic bodily structure of the organism. Nutrient is the term used for these substances.
In humans, nutrients are usually classified into categories like carbohydrates, fats, proteins, minerals, vitamins and water. There are several nutrients that the human body cannot survive without and these are called essential nutrients, examples include proteins, fats, water, etc. Others can be substituted by the essential nutrients or it can be said that their absence does affect survival, examples of these are carbohydrates, substances like anti-oxidants, etc.
If what you are looking for is a paraphrase of the definition found in the dictionary for the purpose of an open-ended question, then look first at the key word: “Nourishment”.
For your answer, you may want to consider that nutrition is a process by which we provide nourishment to our bodies through the intake of minerals and nutrients found in food, or in dietary supplements. Nutrition is a necessary process to maintain our organs healthy enough to continue to perform their functions within our bodies. A good nutrition consists on the ingestion of supplements and food that provide the body with nutritional elements of primary importance. They include iron, potassium, vitamins, magnesium, zinc, and calcium. Contrarily, consuming food products that do not provide any nutritional value (for example, excess fats, oils, sugar, carbohydrates, and sodium) may lead to an adverse bodily reaction that may weaken our bodies to the point of physical and psychological illness. Therefore, a good nutrition is imperative for proper body functioning.
I hope this helps!!!