U : adj : (chiefly British) of or appropriate to the upper classes
especially in language use
(noun) 1: a nitrogen-containing base found in RNA (but not in DNA) and
derived from pyrimidine; pairs with adenine [syn: uracil,
U]
2: a heavy toxic silvery-white radioactive metallic element;
occurs in many isotopes; used for nuclear fuels and
nuclear weapons [syn: uranium, U, atomic number 92]
3: the 21st letter of the Roman alphabet [syn: U]
