A person who conducts experiments; a scientist or researcher who designs and performs tests to discover or verify something.
From experiment (verb) + -er (agent suffix meaning 'one who'). Experiment comes from Latin experimentum. The -er suffix is one of the most productive in English for creating agent nouns (baker, teacher, runner, etc.).
Every experimenter has a story of an experiment that went hilariously wrong—and many of the greatest scientific discoveries came from accidents that experimenters noticed while things were breaking or behaving unexpectedly!
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