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