tab (1) — ODE

tab1 /tab

▸ noun

1 a small flap or strip of material attached to or projecting from something, used to hold, fasten, or manipulate it, or for identification and information.

▪ Military British English a marking on the collar distinguishing an officer of high rank or (formerly) a staff officer.

▪ North American English a strip or ring of metal attached to the top of a canned drink and pulled to open the can.

2 Computing a second or further document or page that can be opened on a web browser or spreadsheet.

3 informal mainly North American English a restaurant bill:

the waiter brought three drinks and a new tab.

▪ a tally of items ordered in a bar or restaurant:

Bobby had told the barman to put everything on the tab.

4 (tabs) short for tableau curtains

5 Aeronautics a part of a control surface, typically hinged, that modifies the action or response of the surface.

6 Northern England informal a cigarette.

▸ verb

( tabs, tabbing, tabbed)

[with object] mark or identify with a projecting piece of material:

he opened the book at a page tabbed by a cloth bookmark.

▪ mainly North American English identify as being of a specified type or suitable for a specified position:

he was tabbed as an astronaut candidate in 1992.

– PHRASES

keep tabs on (also keep a tab on) informal
monitor the activities or development of; keep under observation:

they liked to keep tabs on their former employees.

pick up the tab informal
pay for something:

my company will pick up the tab for all moving expenses.

– DERIVATIVES

tabbed adjective

– ORIGIN late Middle English: perhaps related to tag1.