ovum

例句：

1. 1. The ovum is the female reproductive cell that develops into a fetus.
   卵是发育成胎儿的女性生殖细胞。
2. 2. In fertilization, the sperm and egg combine to form a new ovum.
   在受精过程中，精子和卵子结合形成新的卵。
3. 3. Ovum is also used in medicine to refer to the embryonic stage of development.
   卵也用于医学中，指发育的胚胎阶段。