A RGB-LED has red, green and blue, so 3 leds in one.
A RGBW-LED has red, green, blue and white, so 4 leds in one.
And sure you can let a RGB-LED shine white, but that does not make it a RGBW-LED.
upload://bAe0XRlViOLIXWFuszuGx20mzOd.jpeg
Unfortunately the forum doesn’t let me post links or pictures.