An egg which contains the female genes and is found within the plant ovary – when fertilized, an ovule will grow into a seed.
Merriam-Webster Online Dictionary
ovule (noun)1.
an outgrowth of the ovary of a seed plant that is a megasporangium and encloses an embryo sac within a nucellus
2.
a small egg , especially one in an early stage of growth
seed precursor, plant egg, embryonic seed, immature seed, proto-seed