Is being a research fellow a job?

No, being a research fellow is not a job. Research fellowships are often project or term-based positions. Once the project or term has expired, many research fellows move on to other positions, such as research associate if they're interested in continuing their research as a profession.

Research associates often maintain their title and are seen as employees. These individuals may continue working in the academic setting without issues like terms ending or grants running thin. Research associates are excellent progressive positions after research fellowships end within an institution or other academic facility.