The Collaborative International Dictionary of English v.0.48:

Omnipresence \Om`ni*pres"ence\ ([o^]m`n[i^]*pr[e^]z"ens), n.
   [Cf. F. omnipr['e]sence.]
   Presence in every place at the same time; unbounded or
   universal presence; ubiquity.
   [1913 Webster]

         His omnipresence fills
         Land, sea, and air, and every kind that lives.
                                                  --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

omnipresence
    n 1: the state of being everywhere at once (or seeming to be
         everywhere at once) [syn: ubiquity, ubiquitousness,
         omnipresence]

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "omnipresence":
   completeness, comprehensiveness, entireness, entirety, eternity,
   everywhereness, exhaustiveness, glory, holiness, immutability,
   inclusiveness, infinite goodness, infinite justice, infinite love,
   infinite mercy, infinite power, infinite wisdom, infinity,
   intactness, integrality, integrity, light, majesty, omnipotence,
   omnipotency, omniscience, omnisciency, pervasiveness, solidarity,
   solidity, sovereignty, thoroughness, totality, ubiquity, unity,
   universality, wholeness