What is the process of cell specialization called?

Cell differentiation:

1. The process by which a single cell after division becomes a distinct cell type according to its function.
2. Cell differentiation is a process by which a particular cell becomes specific or specialized.
3. In the human body stem cells can differentiate multiple cell types, as these cells can continuously divide to differentiate into different cell types.
4. During the development of the embryo, the zygote also undergoes differentiation