The Collaborative International Dictionary of English v.0.48:

Interaxis \In`ter*ax"is\, n.; pl. Interaxes. (Arch.)
   The space between two axes. See Axis, 6.
   [1913 Webster]

         The doors, windows, niches, and the like, are then
         placed centrally in the interaxes.       --Gwilt.
   [1913 Webster]