The Collaborative International Dictionary of English v.0.48:

Rota \Ro"ta\, n. (Mus.)
   A species of zither, played like a guitar, used in the Middle
   Ages in church music; -- written also rotta.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rota \Ro"ta\, n. [L. rota wheel. The name is said to allude to
   the design of the floor of the room in which the court used
   to sit, which was that of a wheel. See Rotary.]
   1. An ecclesiastical court of Rome, called also Rota
      Romana, that takes cognizance of suits by appeal. It
      consists of twelve members.
      [1913 Webster]

   2. (Eng. Hist.) A short-lived political club established in
      1659 by J.Harrington to inculcate the democratic doctrine
      of election of the principal officers of the state by
      ballot, and the annual retirement of a portion of
      Parliament.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Rota
    n 1: (Roman Catholic Church) the supreme ecclesiastical tribunal
         for cases appealed to the Holy See from diocesan courts
    2: a roster of names showing the order in which people should
       perform certain duties