light bread vs white bread

light bread and white bread both are nouns.

Word	Noun	Adjective	Verb	Adverb
light bread	Yes	No	No	No
white bread	Yes	No	No	No

As nouns, light bread and white bread are synonyms defined as:

light bread and white bread: bread made with finely ground and usually bleached wheat flour

light bread (noun)	white bread (noun)
bread made with finely ground and usually bleached wheat flour	bread made with finely ground and usually bleached wheat flour