What is the Difference Between Similar But Different Things, Terms, and Objects

What is the Difference between Volatile and Nonvolatile Memory

The computer system has two types of memories in general; one is called volatile and the other is non-volatile. The word volatile is used for these devices because of their temporary or permanent data storage capacities. Memory means the data storage capacity in a device. Like we have brain a part of it is volatile and a part of it is non-volatile, how?