a fat-soluble yellow unsaturated alcohol occurring in green and yellow vegetables (esp carrots), butter, egg yolk, and fish-liver oil (esp halibut oil). It is essential for the prevention of night blindness and the protection of epithelial tissue. Formula: C20H30O
Also called: vitamin A1, retinol
vitamin A in American English
a fat-soluble aliphatic alcohol, C20H29OH, found in fish-liver oil, egg yolk, butter, etc. or derived from carotene in carrots and other vegetables: a deficiency of this vitamin results in night blindness, a general susceptibility to infections, and degeneration of epithelial tissue: it usually occurs in two forms, vitamin A1, having the formula above, and vitamin A2, C20H27OH