Final answer:
A semiconductor is a material that has a conductivity level between that of an insulator and a conductor, exemplified by elements like silicon.
Step-by-step explanation:
A semiconductor can be considered as an intermediate class of material that conducts electricity better than an insulator but not as well as a conductor.
In essence, a semiconductor, such as silicon, is a material that has a filled valence band and an unfilled conduction band with a relatively small energy gap between them. This energy gap allows electrons to be excited from the valence band to the conduction band under certain conditions, like temperature changes or doping. Doping is a process where impurities are added to the semiconductor to change its electrical properties. Conductors, on the other hand, have a large number of free charge carriers, making them good at conducting electricity. Insulators have very few free carriers, leading to poor conductivity. Semiconductors lie between these two extremes, and their ability to conduct electricity can be precisely controlled, which is essential in electronics and computer chip manufacturing.