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vitamin

American  
[vahy-tuh-min, vit-uh-min] / ˈvaɪ tə mɪn, ˈvɪt ə mɪn /
British also vitamine

noun

  • vitamins
    plural
  1. any of a group of organic substances essential in small quantities to normal metabolism, found in minute amounts in natural foodstuffs or sometimes produced synthetically: deficiencies of vitamins produce specific disorders.


vitamin British  
/ ˈvɪtəmɪn, ˈvaɪ- /

noun

  1. any of a group of substances that are essential, in small quantities, for the normal functioning of metabolism in the body. They cannot usually be synthesized in the body but they occur naturally in certain foods: insufficient supply of any particular vitamin results in a deficiency disease

"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

vitamin Scientific  
/ vītə-mĭn /
  1. Any of various organic compounds that are needed in small amounts for normal growth and activity of the body. Most vitamins cannot be synthesized by the body, but are found naturally in foods obtained from plants and animals. Vitamins are either water-soluble or fat-soluble. Most water-soluble vitamins, such as the vitamin B complex, act as catalysts and coenzymes in metabolic processes and energy transfer and are excreted fairly rapidly. Fat-soluble vitamins, such as vitamins A, D, and E are necessary for the function or structural integrity of specific body tissues and membranes and are retained in the body.


Closer Look

Although it has been known for thousands of years that certain diseases can be treated with specific foods, the scientific link between vitamins and good health wasn't made until the early 1900s by Polish-born American biochemist Casimir Funk. While studying beriberi, a disease that causes depression, fatigue, and nerve damage, Funk discovered an organic compound in rice husks that prevents the illness. He named the compound vitamine, derived from the chemical name amine and the Latin word vita, "life," because vitamins are required for life and were originally thought to be amines. Funk's compound is now known as vitamin B1, or thiamine. His research and discovery led him, along with English biochemist Sir Frederick Gowland Hopkins, to propose the vitamin hypothesis of deficiency, which stated that certain diseases, such as scurvy or rickets, are caused by dietary deficiencies and can be avoided by taking vitamins. Further research allowed scientists to isolate and identify the vitamins that we know today to be essential for human health. Vitamins include A, C, D, E, K, thiamine, riboflavin, niacin, B6, B12, folic acid, biotin, and pantothenic acid. Vitamins are distinguished from minerals, such as calcium, iron, and magnesium, which are also essential for optimum health.

Other Word Forms

Derived Forms

Inflected Forms

Nouns

Etymology

Origin of vitamin

1912; earlier vitamine < Latin vīt ( a ) life + amine; coined by C. Funk, who thought they were amines

Explanation

A vitamin is an organic substance your body needs to keep working properly. Vitamins are important to health. Your body needs food and water to stay alive, but it also needs vitamins to work properly. You get some Vitamin D from the sun, and lots of Vitamin C from citrus fruits such as oranges. Without vitamins, your immune system can weaken. Many people take vitamins in pill form to help them stay healthy. The word vitamin — originally vitamine — was coined by scientist Casimir Funk in the early 1900s. He combined vita, Latin for "life," with amine, from amino acids.

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Vocabulary lists containing vitamin

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Although chemically similar to the vitamin humans need, this form is not bioavailable to people, meaning the body cannot effectively use it.

From Science Daily Aug. 30, 2026

Using advanced biotechnology and carefully controlled light conditions, the team produced carbon-neutral, nutrient-rich Spirulina biomass containing active vitamin B12.

From Science Daily Aug. 30, 2026

Scientists have found a way to grow Spirulina that produces biologically active vitamin B12 at levels comparable to beef, potentially overcoming one of the biggest nutritional limitations of this widely promoted algae.

From Science Daily Aug. 30, 2026

According to the researchers, this is the first time biologically active vitamin B12 has been reported in Spirulina.

From Science Daily Aug. 30, 2026

My father took a vitamin pill every morning now with his orange juice, but they didn’t seem to be doing much good.

From "The Chosen" by Chaim Potok

Heavily processed milling strips away bran, germ and other nutrients, and while federal law requires such flour to be enriched, the end product still lacks key vitamins, minerals and anti-oxidants.

From Barron's Sep. 3, 2026

Thorne sells supplements including creatine, prenatal vitamins, hormone supplements and other products.

From The Wall Street Journal Aug. 4, 2026

Zoo staff provided ventilation and water to cool her down, and later administered subcutaneous fluids, liver tonics and vitamins.

From BBC Aug. 4, 2026

These approaches are starting to reveal how diet interacts with the body in ways far beyond calories and vitamins.

From Science Daily Jun. 17, 2026

I stopped drinking and smoking, went to all of my appointments, ate right, took my vitamins, the whole nine.

From "The Hate U Give" by Angie Thomas

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