silicon
Pronunciation: /ˈsɪlɪk(ə)n/
noun

Origin:
early 19th century: alteration of earlier silicium, from Latin silex, silic- 'flint', on the pattern of carbon and boron

Do not confuse silicon with silicone. Silicon is a chemical element used in electronic circuits and microchips, whereas silicone is the material used in cosmetic implants.