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,
1. The superior or head of an abbey.
2. One of a class of bishops whose sees were formerly abbeys.
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.