toponomastics

Etymology tree
Ancient Greek τόπος (tópos)
English topo-
Proto-Indo-European *h₁nómn̥
Proto-Hellenic *ónomə
Ancient Greek ὄνομᾰ (ónomă)
Ancient Greek -ᾰ́ζω (-ắzō)
Ancient Greek ὀνομάζω (onomázō)
Proto-Indo-European *-tis
Ancient Greek -τις (-tis)
Ancient Greek -σῐς (-sĭs)
Proto-Indo-European *-kos
Ancient Greek -κός (-kós)
?
Proto-Indo-European *-tós
Proto-Hellenic *-tós
Ancient Greek -τος (-tos)
▲
Ancient Greek -κός (-kós)
?
Ancient Greek -τῐκός (-tĭkós)
Ancient Greek ὀνομᾰστῐκός (onomăstĭkós)bor.
English onomastic
Old English -as
Middle English -es
English -s
English onomastics
English toponomastics
From topo- + onomastics.