The term “public utilities” embraces all properties devoted to a use in which the public has an interest. As currently employed in this country today, it includes water, light, heat, power, and telephone plants; urban, suburban and interurban electric railways; steam railways; the telegraph, express companies and several minor organizations connected with transportation. In a narrower and more local use of the term, its scope is restricted to water, light, heat, power and local telephone utilities, and urban and suburban electric railways.

Central utilities commissions are administrative bodies appointed or elected for the purpose of carrying out legislative acts with reference to public utilities. In the widest sense of the term a central commission is a federal or national commission, of which the Interstate Commerce Commission is the best-known representative. Central Commissions, in the narrower sense of the term, are illustrated by state utilities and railroad commissions. Like many other terms central and local have relative meanings with shifting and overlapping circumferences.