1) Central part of a plant ovule 2) Plant part 3) Plant structure 
• (n.) See Nucleus, 3 (a). • (n.) See Nucleus, 3 (a).
(from the article `seed and fruit`) ...seeds are formed from bodies called ovules contained in the ovary, or basal part of the female plant structure, the pistil. The mature ovule ... [3 related articles]
The central tissue of an ovule. The nucellus contains the embryo sac and is surrounded by integument(s).
Nu·cel'lus noun ; plural Nucelli . [ New Latin , dim. of nux , nucis , a nut.] (Botany) See Nucleus , 3 (a) . 
[n] - central part of a plant ovule
noun central part of a plant ovule; contains the embryo sac
the central cellular mass of the body of the ovule, containing the embryo sac.