The abnormal increase in number of cells is known as

The abnormal increase in the number of cells is known as Hyperplasia.
Hyperplasia is an enlargement of an organ or tissue caused by an increase in the amount of organic tissue that results from cell proliferation.
It may lead to the gross enlargement of an organ, and the term is sometimes confused with benign neoplasia or benign tumor.
In hyperplasia, there is an increase in the number of cells in an organ or tissue that appear normal under a microscope.