Other forms: tabs, tabbed
A tab is a small flap that sticks out so you can grab it, pull it, or find the thing behind it. The paper triangles down the side of a file folder, the little ring on a drinks can, the row of open pages across the top of your browser.
Computers took the word and ran with it: each page open in a browser sits behind its own tab, and the key at the far left of the keyboard is the Tab key, which jumps the cursor to the next box on a form. In a bar or a cafe, a tab is the running bill you settle at the end — put it on my tab, pick up the tab. As a verb you tab through fields without touching the mouse. Keep tabs on someone means watch them closely, and no money changes hands.
1nounsmallA small flap or strip sticking out from the edge of something, there to be gripped, pulled or read.
“She went through the folders until she found the one with the red tab.”
2nountabOne of several pages open side by side in a browser or program, each with its own strip along the top.
“I had fourteen tabs open and no idea which one was playing the music.”
3nounbillA running bill in a bar or restaurant that you pay at the end.
“Start a tab and we will settle it before we leave.”
4nouncursorThe key on a keyboard that moves the cursor along to the next stop or column.
“Press tab to jump to the next field.”
5verbusingTo move from one field or page to the next using the tab key.
“You can tab from box to box without lifting your hands off the keyboard.”
tab is a small flap or strip.
Tab shows up in English writing in 1607 and the trail stops there. No parent language has ever been agreed on — not Latin, not French, not Norse — so it sits in the dictionary with the flat note 'of uncertain origin'. A four-hundred-year-old word with no known family, now attached to every browser window on earth.
First attested 1607, of uncertain origin.
Etymology from Wiktionary, CC BY-SA