The Collaborative International Dictionary of English v.0.48:

Abbot \Ab"bot\ ([a^]b"b[u^]t), n. [AS. abbod, abbad, L. abbas,
   abbatis, Gr. 'abba^s, fr. Syriac abb[=a] father. Cf. Abba,
   Abb['e].]
   1. The superior or head of an abbey.
      [1913 Webster]

   2. One of a class of bishops whose sees were formerly abbeys.
      --Encyc. Brit.
      [1913 Webster]

   Abbot of the people. a title formerly given to one of the
      chief magistrates in Genoa.

   Abbot of Misrule (or Lord of Misrule), in medi[ae]val
      times, the master of revels, as at Christmas; in Scotland
      called the Abbot of Unreason. --Encyc. Brit.
      [1913 Webster]