Adipocyte: A fat cell, a connective tissue cell that has differentiated and become specialized in the synthesis (manufacture) and storage of fat.

The adipocyte is important to the body in maintaining proper energy balance, storing calories in the form of lipids, mobilizing energy sources in response to hormonal stimulation, and commanding changes by signal secretions.

Under the microscope, the adipocyte appears bloated with triglycerides. The nucleus of the cell is displaced to one side by the fat. The cytoplasm of the cell looks like a thin line surrounding the pool of fat.