1. (noun) a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine

• uracil

2. (noun) a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons

• atomic number 92
• uranium

1. (noun) a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine

• base
• nucleotide

2. (noun) a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons

• metal
• metallic element

3. (noun) the 21st letter of the Roman alphabet

• alphabetic character
• letter
• letter of the alphabet

1. (noun) the 21st letter of the Roman alphabet

• latin alphabet
• roman alphabet

1. (adjective) (chiefly British) of or appropriate to the upper classes especially in language use

• upper-class

1. (noun) a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons

• uranium 235
• uranium 238