Fertilization is the union of an egg cell and sperm, which creates a cell capable of developing into a new animal.

In external fertilization, the process occurs outside the body, usually in water. In the case of internal fertilization, it takes place in the female's reproductive system.

Associated Terms: Fertilisation, Fertilized, Conception, Fecundation, Syngamy

Also see:
Asexual Reproduction
Sexual Reproduction
Parthenogenesis
Internal Fertilization
External Fertilization