Source : Webster's Revised Unabridged Dictionary (1913)

Toponymy \To*pon"y*my\, n.
   A system of toponyms; the use of toponyms. -- {To*pon"y*mal},
   {Top`o*nym"ic}, {Top`o*nym"ic*al}, a.

Source : WordNet®

toponymy
     n 1: the nomenclature of regional anatomy [syn: {toponomy}]
     2: the branch of lexicology that studies the place names of a
        region or a language [syn: {toponomy}]