The prefix meaning 'EGG' is OVO and OVI. OVO is derived from the Latin word for EGG, ovum, while OVI is derived from the Greek word for EGG, oon. Both prefixes are used to refer to something related to eggs, such as ovoviviparous animals, which are animals that lay eggs that hatch inside the mother's body. OVO and OVI are also used in scientific terms, such as ovogenesis, which is the process of EGG formation.