The Collaborative International Dictionary of English v.0.48:

Physiography \Phys`i*og"ra*phy\ (f[i^]z`[i^]*[o^]g"r[.a]*f[y^]),
   n. [Gr. fy`sis nature + -graphy: cf. F. physiographie.]
   1. The science which treats of the earth's exterior physical
      features, climate, life, etc., and of the physical
      movements or changes on the earth's surface, as the
      currents of the atmosphere and ocean, the secular
      variations in heat, moisture, magnetism, etc.; physical
      geography.
      [1913 Webster]

   2. The descriptive part of a natural science as distinguished
      from the explanatory or theoretic part; as, mineral
      physiography.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

physiography
    n 1: the study of physical features of the earth's surface [syn:
         physical geography, physiography]