GO:0036090

Advancement of the cleavage furrow from the outside of the cell inward towards the center of the cell. The cleavage furrow acts as a 'purse string' which draws tight to separate daughter cells during cytokinesis and partition the cytoplasm between the two daughter cells. The furrow ingresses until a cytoplasmic bridge is formed. [PMID:15811947, PMID:20687468]