semiconductor UK /ˌsɛmikənˈdʌktə/US /ˌsɛmikənˈdʌktɚ/ noun2 •A substance with electrical properties intermediate between a good conductor and a good insulator.Integrated circuits are made from semiconductors, especially silicon. •Ellipsis of semiconductor device.The company supplies semiconductors to laptop, server, and smartphone manufacturers. formssemiconductors