corset

Corset comes from Middle English corset, borrowed from Old French corset, which is simply corse plus the diminutive suffix -et.

The facts here don't trace a shift in meaning — the word arrives in English already naming the close-fitting body garment, built from 'corse' plus a small, diminutive ending.

Corset shares its root corse with words meaning 'body' — the -et ending marking it as a small or fitted version of that idea.