vitamin a

from WordNet (r) 3.0 (2006)

vitamin A
    n 1: any of several fat-soluble vitamins essential for normal
         vision; prevents night blindness or inflammation or dryness
         of the eyes [syn: {vitamin A}, {antiophthalmic factor},
         {axerophthol}, {A}]

from The Collaborative International Dictionary of English v.0.48

Retinol \Ret"i*nol\, n. [Gr. ??? resin + L. oleum oil.]
   1. (Chem.) A hydrocarbon oil {C32H16}, obtained by the
      distillation of resin, -- used as a solvent, as an
      antiseptic, and in printer's ink.
      [1913 Webster +PJC]

   2. One of the compounds which function as vitamin A. Called
      also {vitamin A}, {vitamin A1} and {vitamin A alcohol}.
      See {vitamin A1}.
      [PJC]

from The Collaborative International Dictionary of English v.0.48

vitamin A \vitamin A\ n.
   any of several related fat-soluble vitamins (such as retinol)
   essential for normal vision; it also prevents night blindness
   or inflammation or dryness of the eyes.

   Syn: antiophthalmic factor, axerophthol.
        [WordNet 1.5]

from The Collaborative International Dictionary of English v.0.48

vitamin A1 \vitamin A1\ n.
   retinol ({C20H30O}), one of the substances also called
   {vitamin A}. It is also called more specifically {vitamin A
   alcohol}. It is a required factor for human nutrition. The
   USP unit of activity is equal to 0.30 micrograms of retinol.

   Syn: retinol.
        [WordNet 1.5 +PJC]

from The Collaborative International Dictionary of English v.0.48

vitamin A2 \vitamin A2\ n.
   dehydroretinol ({C20H28O}), one of the substances also called
   {vitamin A}. It has about 40% of the bioactivity of vitamin
   A1.

   Syn: dehydroretinol.
        [WordNet 1.5 +PJC]

from The Collaborative International Dictionary of English v.0.48

axerophthol \axerophthol\ n.
   1. a vitamin essential for normal vision ({C20H30O}); it
      prevents night blindness or inflammation or dryness of the
      eyes; same as {vitamin A}. One U.S.P. unit of vitamin A is
      equivalent to 0.30 micrograms of pure vitamin A alcohol.

   Syn: vitamin A; vitamin A alcohol; antiophthalmic factor;
        biosterol; retinol; A.
        [WordNet 1.5 +PJC]

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