Telephone: A device that converts sound into electrical signals that can be transmitted over distances and then converts received signals back into sounds.
Patent: A government authority or license conferring a right or title for a set period, especially the sole right to exclude others from making, using, or selling an invention.
Elisha Gray: An American electrical engineer who co-founded the Western Electric Manufacturing Company. Gray is best known for his development of a telephone prototype in 1876 in Highland Park, Illinois.