research
Research is the patient, systematic search for knowledge — gathering evidence, testing a hypothesis, and building conclusions you can defend. The word comes through French from re- and cercher, 'to seek again', and that repetition is the point: research circles back, checks, and scrutinizes until a finding holds. As a noun it is almost always uncountable — you do research, not 'a research', a slip that trips up many candidates. As a verb, to research a topic is to investigate it methodically rather than to guess.
- iYears of research were needed to substantiate the drug's safety.
- iiHer research focuses on how coral reefs adapt to warming oceans.
- iiiCareful research lets you infer general patterns from limited data.
- conduct research
- carry out research
- a body of research
- research suggests
- extensive research
Family researcher (noun) · researched (adjective)
=investigation, study, inquiry, examination, analysis
Extremely high-frequency and a classic accuracy trap: research is uncountable, so write 'a piece of research' or 'some research', never 'a research' or 'researches'. Build the collocations — 'conduct / carry out research', 'research suggests / indicates', 'a body of research'. Note the US–UK stress difference (REsearch vs reSEARCH). It is indispensable for TOEFL integrated writing, where you report what research shows.