A metalloid, in one form or another, that conducts electricity more easily than a true nonmetal but less easily than a metal; e.g., silicon, germanium.
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semi·con·duc·tor -kən-'dək-tər n any of a class of solids (as germanium or silicon) whose electrical conductivity is between that of a conductor and that of an insulator in being nearly as great as that of a metal at high temperatures and nearly absent at low temperatures
Medical dictionary. 2011.