Amoled display is a display technology invented by Samsung . In an AMOLED display both the backlight of the screen and the screen itself are LED.
The word AMOLED stands for ‘Active Matrix Organic Light Emitting Diode’.
Retina display is the one used by Apple in its displays, It’s called retina display because the pixel density is high enough that individual pixels are not visible at “normal viewing distance”
Difference in AMOLED and RETINA display: Both Retina and AMOLED display are termed as LED displays, but in reality Retina displays only have LED in backlight, while the front screen is a LCD.