The stock ticker was invented by Edward A. Calahan of the American Telegraph Company in 1867. It was later improved by Thomas Edison. The stock ticker was a device that transmitted stock prices over the telegraph lines and printed them on a strip of paper. It was in use primarily in the 1900s, and got its name because of the characteristic clicking or ticking sound of the telegraph.
Today the term “ticker” or “ticker tape” refers to a device that shows the price and volumes of stock trades as they become available. An example would be the ticker tape that runs across the bottom of your TV screen while you watch a financial channel.