Cybernetics were technological replacements or enhancements for organic body parts, including eyes, limbs, and, in extreme cases, the majority of an individual's body, including whole new organ systems. A cyborg was an organic being who had the majority of their body replaced by cybernetics.
General Grievous, the cyborg leader of the Separatist Droid Army, had most of his body replaced by cybernetics. Anakin Skywalker had a cybernetic right forearm installed to replace the lost appendage after his duel with Count Dooku, and when he became Darth Vader, he was rebuilt with cybernetic parts by medical droids after having his limbs severed and nearly being burned to death. Luke Skywalker had a cybernetic right hand installed to replace the lost appendage after his duel with Darth Vader. The Junkers, a species from the planet Lotho Minor, regularly augmented their bodies with cybernetic enhancements.
Denetrius Vidian once thought of getting cybernetic implants that would give him near-total memory recall, but decided against it; afraid of possibly harming any brain chemistry that gave him his perceived genius.