noun Cell Biology.
- one of a pair of structurally dissimilar gametes, the female gamete being large and nonmotile and the male gamete being small and motile.
- sexual reproduction involving a small motile male gamete and a large much less motile female gamete: occurs in all higher animals and some plants
- A female gamete, especially the larger of two gametes produced by an oogamous species.
- A system of sexual reproduction in which one gamete (called the egg) is large and nonmotile, while the other (called the sperm) is small and motile. Oogamy is a type of heterogamy. Compare isogamy.