zygote is called monozygotic, from two zygotes is called dizygotic, or from three or more zygotes is called polyzygotic. Similarly, the siblings themselves from a multiple birth may be referred to as monozygotic if they are identical or as dizygotic (in cases of twins) or polyzygotic (for three or more siblings) if they are fraternal, i.e., non-identical.

Each fertilized ovum (zygote)