The Collaborative International Dictionary of English v.0.48:

Stationariness \Sta"tion*a*ri*ness\ (-[asl]*r[i^]*n[e^]s), n.
   The quality or state of being stationary; fixity.
   [1913 Webster]

WordNet (r) 3.0 (2006):

stationariness
    n 1: remaining in place [syn: stationariness, immobility,
         fixedness]