Refresh rate is defined as how often your screen can display an image per second and is measured in hertz (Hz). So, a monitor with an advertised refresh rate of 240 Hz refreshes the image 240 times per second. However, to hit 240 Hz or the high watermark of 360 Hz, you're not just dependent on your monitor.
Most gaming monitors have a minimum 120 Hz refresh rate and ramp up from there. Generally, the higher the number, the better performance you'll see with a smoother picture. However, you'll also need a powerful CPU and one of the best graphics cards for gaming capable of outputting pixels at a rate fast enough to keep up.
While 360 Hz has been the gold standard for quite some time, BOE is ramping performance even further with what it claims is the world's first 500 Hz gaming monitor. However, the monitor is currently in the prototype stages, and graphics cards capable of driving it to its fullest potential are at least a few generations away.
The higher the refresh rate, the smoother gameplay will appear on the monitor. That's why professional eSports gamers tend to prefer an FHD or QHD monitor with a high refresh rate over one with a higher 4K resolution.
This article is part of the Tom's Hardware Glossary.