A Manor is a term originating from Feudal times, similar timeframe to Baronies. A manor would be similar to an estate or Demesne and relate to an individuals property - usually granted to him or an ancestor, so probably would not correspond exactly to any of the later land divisions. The term was also used in England and other parts of Europe. There are some introductory articles on the concepts which mention Baronies and Manors on Wikipedia - see : Manorialism and Barony (Ireland)
There's a specific mention of the Manor of Skeagh in an article on the Schools Collection at Duchas.ie for Knockbride, Co. Cavan which mentions the landlord, probably the Lord of the Manor, a Sir George Hudson - see the evictions of Skeagh
EDIT : the Wikipedia links are failing to display, even though I can see them in the editor - for the first search Wikipedia for Manorialism, for the 2nd search for Barony (Ireland)