The Collaborative International Dictionary of English v.0.48:

Recumbency \Re*cum"ben*cy\ (-ben*s?), n.
   Recumbence.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "recumbency":
   accubation, accumbency, couchancy, debasement, decumbency,
   depression, loll, lounging, lowness, lying, lying down, proneness,
   prostration, reclination, reclining, repose, shortness, sprawl,
   squatness, squattiness, stumpiness, subjacency, supineness