vitamin E

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several fat-soluble vitamins consisting of tocopherols, especially alpha-tocopherol, that are found chiefly in vegetable oils, nuts and seeds, wheat germ, leafy green vegetables, and milk and act as antioxidants in the body.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of several fat-soluble vitamins, found in plants, that act as antioxidants and are essential for reproduction; the tocopherols.