The Collaborative International Dictionary of English v.0.48:

Abbacy \Ab"ba*cy\ ([a^]b"b[.a]*s[y^]), n.; pl. Abbacies
   (-s[i^]z). [L. abbatia, fr. abbas, abbatis, abbot. See
   Abbey.]
   The dignity, estate, or jurisdiction of an abbot.
   [1913 Webster]