A worker who assembles, installs, or adjusts machinery or equipment, or someone who fits clothes to a person's body.
From 'fit' (possibly from Old Norse 'fit,' meaning a section or piece) plus the agent suffix '-er.' Industrial fitters became essential workers in the 19th century with factory production.
In British English, a 'fitter' is a highly skilled tradesperson—more respected than the term might suggest—because fitting complex machinery requires years of training and precision!
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