In human–computer interaction, a cursor is an indicator used to show the current position on a computer monitor or other display device that will respond to input.
Cursor is Latin for 'runner'. A cursor is a name given to the transparent slide engraved with a hairline used to mark a point on a slide rule. The term was then transferred to computers through analogy.
On 14 November 1963, while attending a conference on computer graphics in Reno, Nevada, Douglas Engelbart of Augmentation Research Center (ARC) first expressed his thoughts to pursue his objective of developing both hardware and software computer technology to "augment" human intelligence by pondering how to adapt the underlying principles of the planimeter to inputting X- and Y-coordinate data, and envisioned something like the cursor of a mouse he initially called a "bug", which, in a "3-point" form, could have a "drop point and 2 orthogonal wheels". He wrote that the "bug" would be "easier" and "more natural" to use, and unlike a stylus, it would stay still when let go, which meant it would be "much better for coordination with the keyboard."
According to Roger Bates, a young hardware designer at ARC under Bill English, the cursor on the screen was for some unknown reason also referred to as "CAT" at the time, which led to calling the new pointing device a "mouse" as well.
Text field
In most command-line interfaces or text editors, the text cursor, also known as a caret, is an underscore, a solid rectangle, or a vertical line, which may be flashing or steady, indicating where text will be placed when entered (the insertion point). In text mode displays, it was not possible to show a vertical bar between characters to show where the new text would be inserted, so an underscore or block cursor was used instead. In situations where a block was used, the block was usually created by inverting the pixels of the character using the boolean math exclusive or function. On text editors and word processors of modern design on bitmapped displays, the vertical bar is typically used instead.