triglyceride
    n 1: glyceride occurring naturally in animal and vegetable
         tissues; it consists of three individual fatty acids bound
         together in a single large molecule; an important energy
         source forming much of the fat stored by the body

Triglyceride \Tri*glyc"er*ide\, n. [Pref. tri- + glyceride.]
   (Chem.)
   A glyceride formed by the replacement of three hydrogen atoms
   in glycerin by acid radicals.
   [1913 Webster]