Notochord is derived from 

The notochord is derived from the mesoderm during embryonic development. The mesoderm is one of the three primary germ layers formed during gastrulation, and it gives rise to various structures in the developing embryo, including the notochord.

The notochord is a flexible rod-like structure that provides support to the developing embryo. It serves as a temporary axial structure and plays a crucial role in signaling and patterning during early development. In many vertebrates, the notochord is eventually replaced by the vertebral column or backbone, which forms from the mesoderm as well.