There are plenty of new and confusing terms facing TV shoppers today, but when it comes down to the screen technology itself, there are only two: Nearly every TV sold today is either OLED or LCD. There are many OLED products on the market, such as transparent OLED TVs, transparent monitors, etc.
The largest between them is in how they work. With an LCD TV, all of the pixels are illuminated by an LED backlight. With OLED, each pixel provides its own illumination so there's no separate backlight. That difference leads to all kinds of picture quality effects, some of which favor LCD, but most of which benefit OLED.