ˈnaɪtrədʒən n. Chem. a
colourless tasteless odourless
gaseous element that forms four-fifths of
the atmosphere and is an
essential constituent of proteins and nucleic acids. °Symb.: N. ønitrogen
cycle the interconversion of nitrogen and
its compounds, usu. in the
form of nitrates, in
nature. nitrogen
fixation a
chemical process in
which atmospheric nitrogen is assimilated
into organic compounds in
living organisms and
hence into the nitrogen cycle. øønitrogenous adj. [F nitrogëne (as
NITRO-, -GEN)]