An egg is the organic vessel containing the zygote in which an animal embryo develops until it can survive on its own, at which point the animal hatches. An egg results from fertilization of an ovum. Most arthropods, vertebrates, and mollusks lay eggs, although some do not, such as scorpions and most mammals.

The EGG file format is a compressed archive file format that supports for Unicode and intelligent compression algorithms. EGG format is created by ESTsoft and was first applied in their file compression software ALZip.

An egg is an organic vessel in which an embryo begins to develop.