IOPS stands for Input/Output Operations Per Second. It's like asking how many toys can you play with in a minute. Now, imagine there's a toy box with different kinds of toys, and you want to take them out and put them back in the box as fast as possible. That's what IOPS is but with a computer, and instead of toys, it's data. It describes how quickly a computer can read and write data to a storage device like a hard drive or solid-state drive.
When you do anything on a computer, like opening a program or saving a file, your computer has to read or write data to your storage device. The speed at which it can do this is measured in IOPS. The higher the IOPS, the faster things will load and save, and the faster your computer will run.
Think of it like a checkout line at a store. The more checkout lanes there are, the more quickly people can move through the line and get out of the store. Similarly, the higher the IOPS of a storage device, the faster your computer can access and save data, making your overall experience much quicker and smoother.