Endocytosis is defined as the process of trapping a particle or substance from the external environment by engulfing it. Endocytosis is of two types viz phagocytosis, also known as cellular eating and pinocytosis, also referred to as cellular drinking.

There are three types of endocytosis:

1. Phagocytosis,

2. Pinocytosis and

3. Receptor-mediated endocytosis.