Source : Webster's Revised Unabridged Dictionary (1913)

Scull \Scull\, n. (Anat.)
   The skull. [Obs.]

Scull \Scull\, n. [See 1st {School}.]
   A shoal of fish. --Milton.

Scull \Scull\, n. [Of uncertain origin; cf. Icel. skola to
   wash.]
   1. (Naut.)
      (a) A boat; a cockboat. See {Sculler}.
      (b) One of a pair of short oars worked by one person.
      (c) A single oar used at the stern in propelling a boat.

   2. (Zo["o]l.) The common skua gull. [Prov. Eng.]

Scull \Scull\, v. t. [imp. & p. p. {Sculled}; p. pr. & vb. n.
   {Sculling}.] (Naut.)
   To impel (a boat) with a pair of sculls, or with a single
   scull or oar worked over the stern obliquely from side to
   side.

Scull \Scull\, v. i.
   To impel a boat with a scull or sculls.

Source : WordNet®

scull
     n 1: a long-handled oar mounted at the stern of a boat and moved
          left and right to propel the boat forward
     2: one of a pair of short-handled oars
     3: a racing shell propelled by one or two oarsmen pulling two
        oars
     v : propel with sculls; "scull the boat"