What is a flower's ovule?

Question

What is a flower's ovule?

Answer 1

In seed plants there are two stages in the life cycle, the sporophyte (the plants we typically see) and the gametophyte (the stage that produces s*x cells).  In flowers, the male gametophyte is the pollen grain composed of two cells and the female is the ovule formed by a total of seven cells and eight nuclei.  The pollen grain forms a pollen tube which conducts two sperm nuclei into the ovule.  One sperm nucleus fertilizes the egg, the other fuses with two nuclei.  The egg forms the zygote and the other fused nuclei form a nutritive tissue called endosperm.

As the zygote develops into the seed, the ovary that contains one or more ovules forms the fruit.

Now you know more than you wanted to know about the ovule.

Answer 2

It's the female part of the flower that has cells that can mature into oocytes (the cells that will form eggs for sperm to fertilize to make a new fertilized seed).  Think of it being like a woman's ovary.