LED vs OLED

LED and OLED both are nouns.

Word	Noun	Adjective	Verb	Adverb
LED	Yes	No	No	No
OLED	Yes	No	No	No

As nouns, OLED is a hyponym of LED; that is, OLED is a word with a more specific, narrower meaning than LED:

LED: diode such that light emitted at a p-n junction is proportional to the bias current; color depends on the material used
OLED: a self-luminous diode (it glows when an electrical field is applied to the electrodes) that does not require backlighting or diffusers

Other hyponyms of LED include organic light-emitting diode.

LED (noun)	OLED (noun)
diode such that light emitted at a p-n junction is proportional to the bias current; color depends on the material used	a self-luminous diode (it glows when an electrical field is applied to the electrodes) that does not require backlighting or diffusers