LED vs light-emitting diode

LED and light-emitting diode both are nouns.

Word	Noun	Adjective	Verb	Adverb
LED	Yes	No	No	No
light-emitting diode	Yes	No	No	No

As nouns, LED and light-emitting diode are synonyms defined as:

LED and light-emitting diode: diode such that light emitted at a p-n junction is proportional to the bias current; color depends on the material used

LED (noun)	light-emitting diode (noun)
diode such that light emitted at a p-n junction is proportional to the bias current; color depends on the material used	diode such that light emitted at a p-n junction is proportional to the bias current; color depends on the material used