The Collaborative International Dictionary of English v.0.48:

Rib \Rib\, v. t. [imp. & p. p. Ribbed; p. pr. & vb. n.
   Ribbing.]
   1. To furnish with ribs; to form with rising lines and
      channels; as, to rib cloth.
      [1913 Webster]

   2. To inclose, as with ribs, and protect; to shut in.
      [1913 Webster]
      [1913 Webster]

            It [lead] were too gross
            To rib her cerecloth in the obscure grave. --Shak.
      [1913 Webster]

   To rib land, to leave strips of undisturbed ground between
      the furrows in plowing.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ribbing \Rib"bing\, n.
   An assemblage or arrangement of ribs, as the timberwork for
   the support of an arch or coved ceiling, the veins in the
   leaves of some plants, ridges in the fabric of cloth, or the
   like.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ribbing
    n 1: a framework of ribs
    2: the act of harassing someone playfully or maliciously
       (especially by ridicule); provoking someone with persistent
       annoyances; "he ignored their teases"; "his ribbing was
       gentle but persistent" [syn: tease, teasing, ribbing,
       tantalization]