The process by which cells increase in number through cell division.

Here's a breakdown:

* Cell division: This is the fundamental process where a single cell divides into two or more daughter cells. The two main types of cell division are mitosis and meiosis.

* Increase in number: Cell proliferation leads to a greater number of cells in a tissue or organism.

* Essential for growth and development: Cell proliferation is vital for growth and development of organisms, tissue repair, and maintaining healthy cell populations.

Therefore, cell proliferation encompasses the entire process of cell division and the resulting increase in cell numbers, which is crucial for various biological processes.