The Collaborative International Dictionary of English v.0.48:

nave \nave\ (n[=a]v), n. [AS. nafu; akin to D. naaf, G. nabe,
   OHG. naba, Icel. n["o]f, Dan. nav, Sw. naf, Skr. n[=a]bhi
   nave and navel: cf. L. umbo boss of a shield. [root]260. Cf.
   Navel.]
   1. The block in the center of a wheel, from which the spokes
      radiate, and through which the axle passes; -- called also
      hub or hob.
      [1913 Webster]

   2. The navel. [Obs.] --hak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Nave \Nave\, n. [F. nef, fr. L. navis ship, to which the church
   was often likened; akin to Gr. nay`archo`s, Skr. n[=a]us, and
   perh. to AS. naca boat, G. nachen, Icel. n["o]kkvi; cf. L.
   nare to swim, float. Cf. Nausea, Nautical, Naval.]
   (Arch.)
   The middle or body of a church, extending from the transepts
   to the principal entrances, or, if there are no transepts,
   from the choir to the principal entrance, but not including
   the aisles.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nave
    n 1: the central area of a church

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "nave":
   Easter sepulcher, ambry, apse, arbor, axis, axle, axle bar,
   axle shaft, axle spindle, axle-tree, baptistery, blindstory,
   center, center of action, center of gravity, centroid, centrum,
   chancel, choir, cloisters, confessional, confessionary, core,
   crypt, dead center, diaconicon, diaconicum, distaff, epicenter,
   fulcrum, gimbal, gudgeon, heart, hinge, hingle, hub, kernel,
   mandrel, marrow, medulla, metacenter, middle, navel, nub, nucleus,
   oarlock, omphalos, pin, pintle, pith, pivot, pole, porch,
   presbytery, radiant, rood loft, rood stair, rood tower, rowlock,
   sacrarium, sacristy, spindle, storm center, swivel, transept,
   triforium, trunnion, umbilicus, vestry