vitamin C, C, ascorbic acid(noun)

a vitamin found in fresh fruits (especially citrus fruits) and vegetables; prevents scurvy

vitamin C(Noun)

The L-enantiomer of ascorbic acid, a water-soluble nutrient essential for life, synthesized by most animals and plants but not humans, although used in our bodies for many purposes. It is plentiful in citrous fruits and many vegetables, and a deficiency causes scurvy.