Platonism

Etymology tree
Proto-Indo-European *pleth₂-
Proto-Indo-European *-us
Proto-Indo-European *pléth₂us
Proto-Hellenic *plətús
Ancient Greek πλατύς (platús)
Ancient Greek -ων (-ōn)
Ancient Greek Πλάτων (Plátōn)
Proto-Indo-European *-id-
Proto-Indo-European *-yéti
Proto-Indo-European *-idyéti
Proto-Hellenic *-íďďō
Ancient Greek -ῐ́ζω (-ĭ́zō)
Proto-Indo-European *-mos
Proto-Indo-European *-mós
Ancient Greek -μός (-mós)
Ancient Greek -ισμός (-ismós)der.
English -ism
English Platonism
From Ancient Greek Πλάτων (Plátōn, “Plato”) + English -ism.