noun

• (uncountable, countable in some dialects) Diligent inquiry or examination to seek or revise facts, principles, theories, applications, etc. (that are currently available, or that are familiar to one's self).
  "In an era when political leaders promise deliverance from decline through America’s purported preeminence in scientific research, the news that science is in deep trouble in the United States has been as unwelcome as a diagnosis of leukemia following the loss of health insurance."
• (countable, dated) A particular instance or piece of research.
  "The dearest interests of parties have frequently been staked on the results of the researches of antiquaries."

verb

• (transitive) To search or examine with continued care; to seek diligently.
• (intransitive) To make an extensive investigation into.
• (transitive) To search again.
• (intransitive, marketing) To receive a certain response in market research.
  "Agency and bank staff told the newspaper the ad researched well."