In the context of anatomy and physiology, development is the process by which an organism grows and differentiates from a simple to a more complex form. This encompasses all changes an organism undergoes from the fertilized egg (zygote) through to maturity and aging.
Related terms
Differentiation: The process by which unspecialized cells become specialized into one of many cell types with specific functions within the body.
Growth: An increase in size and mass of an organism or its parts due to cell proliferation and synthesis of new material.
Maturation: The final stages of development in which cells, tissues, organs, and systems reach their fully functional adult form