What are basic logic gates? Why are they called so?

Basic logic gates are the fundamental logic gates that are independent and not derived from any other gates. There are three basic logic gates — AND gate, OR gate and NOT gate.

They are called basic or fundamental logic gates because they are independent and cannot be constructed using other gates. On the contrary, all other logic gates (such as NAND, NOR, XOR, etc.) are derived from these three basic gates by combining two or more of them. Hence, these gates form the foundation for designing all other complex logical circuits.