noun: (countable) Initialism of question & answer.
noun: (countable) Initialism of quixotic agitator.
noun: (uncountable) Initialism of quality assurance. [A system in which the delivery of a service or the quality of a product is assessed, and compared with that required.]
noun: (uncountable, chemistry) Initialism of quaternary ammonium. [(chemistry) An ammonium group in which each hydrogen has been replaced by an alkyl or aryl group]