An obsessive interest in or feeling about someone or something
his sports fixation has gotten intolerable
The incorporation of carbon into organic compounds by living organisms, chiefly by photosynthesis in green plants
A fixation on one's mother.
The chemical processes by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle
A test for infection with a microorganism that involves measuring the amount of complement available in serum to bind with an antibody-antigen complex