tab 1 
(tăb)
(tăb)n.
1. A projection, flap, or short strip attached to an object to facilitate opening, handling, or identification.
2. A small, usually decorative flap or tongue on a garment.
3. A small auxiliary airfoil that is attached to a larger one and that helps stabilize an aircraft.
4. A pull-tab.
tr.v. tabbed, tab·bing, tabs
To supply with a tab or tabs.
[Origin unknown.]