Guilford Transportation Industries (Guilford) (defendant) entered into an agreement with Central Maine Power Company (CMP) (plaintiff) that granted CMP the ability to, among other things, lay appurtenances across Guilford’s land. Appurtenances were defined as pipes, poles, wires, and other equipment. The agreement did not contain a definition of wire. CMP was required to pay a fee to Guilford in accordance with a fee schedule based on the voltage of the wire. The fee schedule established the fee at $75 annually for wires carrying between zero and 750 volts. CMP requested to install fiber-optic cable under the agreement, and Guilford refused. Guilford asserted that the term “wire” in the agreement only referred to strands of metal capable of carrying electric current. Fiber-optic cable was made of glass and did not carry electrical current. Another provision of the agreement did refer to appurtenances, which consisted of electric power or communication wires and equipment. CMP requested that an administrative agency, the Public Utilities Commission (PUC), resolve the contractual dispute. The PUC granted summary judgment to CMP, and Guilford appealed the decision to the Maine Supreme Judicial Court.