Final answer:
The lathe is referred to as the mother machine tool because of its essential role in manufacturing and its capability to produce other tools.
Step-by-step explanation:
The machine tool known as the mother machine tool is the lathe. This designation stems from its fundamental role in the field of machining, where it can perform a variety of operations such as turning, facing, threading, and drilling. The lathe's versatility makes it indispensable to the manufacturing process, and it's often used to create other machine tools, hence the title 'mother machine tool.' The ability of the lathe to produce precise cylindrical parts has been essential to technological advancements across numerous industries.