noun
(uncountable) The branch of natural science that deals with the composition and constitution of substances and the changes that they undergo as a consequence of alterations in the constitution of their molecules.
(countable) An application of chemical theory and method to a particular substance.
The chemical properties and reactions of a particular organism, environment etc.
(informal) The mutual attraction between two people; rapport.
(medicine, countable, informal, sometimes proscribed) A blood test to measure the amount of various components of the serum (such as electrolytes, creatinine, and glucose).