S: (n) mechanism (device consisting of a piece of machinery; has moving parts that perform some function)
S: (n) device (an instrumentality invented for a particular purpose) "the device is small enough to wear on your wrist"; "a device intended to conserve water"
S: (n) medicine, practice of medicine (the learned profession that is mastered by graduate training in a medical school and that is devoted to preventing or alleviating or curing diseases and injuries) "he studied medicine at Harvard"