DIT is an abbreviation for the term 'telegraphy click, ' which is a type of communication used to send messages over long distances. Telegraphy click is a method of sending Morse code signals through a telegraph machine, which is a device that converts electrical signals into sound. The sound is then transmitted over a wire or radio waves and received by another telegraph machine. This method of communication was widely used in the 19th century before the invention of the telephone.