The rudiment of a seed. It grows from a placenta, and consists of a soft nucleus within two delicate coatings. The attached base of the ovule is the hilum, the coatings are united with the nucleus at the chalaza, and their minute orifice is the foramen.
- Botany A minute structure in seed plants, containing the embryo sac and surrounded by the nucellus, that develops into a seed after fertilization.
- Zoology A small or immature ovum.