because it is situated on the silicon board with resistors ,transistors and wires.These three things organize electrical circuit.

Integrated = mixed or combined (same usage as "integrated school" in civil rights).

Circuit = electronic circuit.

Integrated Circuit = combination of a variety of components into one inseparable circuit.

There are 2 types of integrated circuits:

• Hybrid integrated circuit = ceramic printed circuit board with ultra-miniaturized components soldered to the pads
• Monolithic integrated circuit = one piece (i.e., single stone) circuit made of silicon (or other semiconductor crystal) with all the different types of components part of that crystal (and layers of metal plated on it to connect components)