tab (Noun) — The bill in a restaurant. ex. "he asked the waiter for the tab"
tab (Noun) — Sensationalist journalism.
tab (Noun) — The key on a typewriter or a word processor that causes a tabulation.
tab (Noun) — A short strip of material attached to or projecting from something in order to facilitate opening or identifying or handling it. ex. "pull the tab to open the can" ex. "files with a red tab will be stored separately" ex. "the collar has a tab with a button hole" ex. "the filing cards were organized by cards having indexed tabs"
tab (Noun) — A dose of medicine in the form of a small pellet.
tab (Noun) — A metal ring that is pulled to open a can.
tab (Verb) — (computing) use the tab key on a computer to navigate the screen or page (e.g. to change the selected item on screen).
tab (Verb) — Mark with a tab.