ribonucleic acid, RNA - (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell; "ribonucleic acid is the genetic material of some viruses"

nucleotide - a phosphoric ester of a nucleoside; the basic structural unit of nucleic acids (DNA or RNA)

metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.

uranium 235 - a uranium isotope with mass number 235; capable of sustaining chain reactions

uranium 238 - the commonest isotope of uranium; it is not fissionable but when irradiated with neutrons it produces fissionable plutonium 239

pitchblende, uraninite - a mineral consisting of uranium oxide and trace amounts of radium and thorium and polonium and lead and helium; uraninite in massive form is called pitchblende which is the chief uranium ore

Latin alphabet, Roman alphabet - the alphabet evolved by the ancient Romans which serves for writing most of the languages of western Europe

alphabetic character, letter of the alphabet, letter - the conventional characters of the alphabet used to represent speech; "his grandmother taught him his letters"

Great Britain, UK, United Kingdom, United Kingdom of Great Britain and Northern Ireland, Britain, GB - a monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern Ireland

upper-class - occupying the highest socioeconomic position in a society