Source : Webster's Revised Unabridged Dictionary (1913)

Bathymetry \Ba*thym"e*try\, n. [Gr. ba`qos depth + -metry.]
   The art or science of sounding, or measuring depths in the
   sea.

Source : WordNet®

bathymetry
     n : measuring the depths of the oceans [syn: {plumbing}]