A bell is a simple sound-making machine. In its most classical form it is a church bell. Bells can be of all sizes: From dress accessories to church bells literally weighing tons. Bells are common for raising attention, and the word is also used for the ringer in telephones, on bicycles and in door bells.
The Bell telephone company was founded by Alexander Graham Bell. In the 19th century Bell was acquired by AT&T, often called Ma Bell, which maintained a telephone monopoly in the United States until 1984. The breakup of AT&T led to the creation of seven regional phone companies, called Baby Bells. The name persists in companies such as Pacific Bell and Southwestern Bell, which are now brands of SBC Communications.
Bell Aircraft manufactured a number of important early aircraft, such as the P-39 Aircobra. They also made a series of research aircraft, including the X-1, the first aircraft to exceed the speed of sound (mach 1).