Plural of fitter; people who fit, install, or adjust things like pipes, clothes, or mechanical parts.
From 'fit' plus the agent noun suffix '-er' (one who does), then pluralized with '-s.' People who fit things have been called fitters since at least the 19th century.
Plumbers, electricians, and tailors are all types of fitters—it's a job category that highlights that their skill is all about making things fit correctly and securely in place.
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