1. the central part of a plant ovule containing the embryo sac
Usage: botanical

Examples

• The nucellus surrounds and protects the developing embryo sac.
• In flowering plants, the nucellus is gradually consumed as the seed develops.
• The botanist examined the nucellus under a microscope to study ovule development.
• Fertilization occurs when pollen reaches the nucellus through the micropyle.
• The nucellus provides nutrients to the growing embryo during seed formation.