What does "tab" mean?

Tab: A tag. See Tag, 2.

Additional senses

  1. 2.A loop for pulling or lifting something.
  2. 3.A border of lace or other material, worn on the inner front edge of ladies' bonnets.
  3. 4.A loose pendent part of a lady's garment; esp., one of a series of pendent squares forming an edge or border.

Sources