The Collaborative International Dictionary of English v.0.48:

Nomadism \Nom"ad*ism\, n.
   The state of being a nomad.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "nomadism":
   Wanderjahr, afoot and lighthearted, bumming, discursion,
   divagation, drifting, errantry, flitting, gadding, hoboism,
   itineracy, itinerancy, peregrination, pererration, ramble,
   rambling, roam, roaming, rove, roving, straying, traipsing,
   vagabondage, vagabondia, vagabondism, vagrancy, wandering,
   wanderlust, wayfaring