English 'prosthesis' comes from Greek 'prostithenai' (to add, to place in addition), from 'pros' (toward) + 'tithenai' (to place), from PIE *dʰeh₁- (to put) — the same root as Latin 'facere' and English 'do' — literally 'something added,' a supplement that completes a body.
An artificial body part, such as a limb, eye, or tooth, used to replace a missing or impaired part of the body.
From Greek 'prosthesis' (πρόσθεσις, an addition, a putting to), from 'prostithenai' (προστιθέναι, to put to, to add, to place in addition), a compound of 'pros' (πρός, to, toward, in addition to) + 'tithenai' (τιθέναι, to place, to put), from PIE *dʰeh₁- (to put, to place, to set). The PIE root *dʰeh₁- is one of the most productive in Indo-European, producing Latin 'facere' (to do, to make), Greek 'tithenai' (to place), and English 'do.' A prosthesis is literally something added — placed in addition to what is there — a supplement that completes
The PIE root *dʰeh₁- (to put, to place) connects 'prosthesis' to both 'do' and 'fact.' In Latin it became 'facere' (to make, to do), producing 'fact,' 'factory,' 'affair,' 'feature,' and 'fashion.' In Greek it became 'tithenai' (to place), producing 'thesis,' 'synthesis,' 'hypothesis,' and 'prosthesis.' In English it became 'do' and 'deed.' The artificial limb and the everyday verb 'to do' share the same six-thousand-year-old root.