The Collaborative International Dictionary of English v.0.48:

Patness \Pat"ness\, n.
   Fitness or appropriateness; striking suitableness;
   convenience.
   [1913 Webster]

         The description with equal patness may suit both.
                                                  --Barrow.
   [1913 Webster]

WordNet (r) 3.0 (2006):

patness
    n 1: timely convenience [syn: opportuneness, patness,
         timeliness] [ant: inopportuneness, untimeliness]