PLUTONIUM 239

 I. (noun) 

Sense 1

Meaning:

A highly fissionable isotope of plutonium that is used in atomic weapons and as a reactor fuel; produced by irradiating uranium 238 with slow electrons

Classified under:

Nouns denoting substances

Hypernyms ("plutonium 239" is a kind of...):

atomic number 94; plutonium; Pu (a solid silvery grey radioactive transuranic element whose atoms can be split when bombarded with neutrons; found in minute quantities in uranium ores but is usually synthesized in nuclear reactors; 13 isotopes are known with the most important being plutonium 239)

Hyponyms (each of the following is a kind of "plutonium 239"):

weapons-grade plutonium; weapons plutonium (plutonium 239 that is recovered when nuclear weapons are disassembled; it is stored in plutonium pits)

Credits