A key on a computer keyboard that, when pressed, inserts a special ASCII character used for formatting text, as in indenting a line or block of text, A projection, flap, or short strip attached to an object to facilitate opening, handling, or identification, a bill or check for some purchase, as in a restaurant, verb_ Short for tabulate, computing To use the Tab key on a computer or typewriter to navigate the screen or page, Mark with a tab, transitive verb_ To supply with a tab or tabs