uracil vs U

uracil and U both are nouns.

Word	Noun	Adjective	Verb	Adverb
uracil	Yes	No	No	No
U	Yes	No	No	No

As nouns, uracil and U are synonyms defined as:

uracil and U: a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine

uracil (noun)	U (noun)
a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine	the 21st letter of the Roman alphabet
	a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons
	a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine