Where does “предположи́ть” come from?
предположи́ть (Russian) comes from Russian положи́ть, from Russian ложи́ть, from Old East Slavic ложити, from Proto-Slavic ložiti, from Proto-Balto-Slavic lágīˀtei, from Proto-Indo-European logʰ-éye-ti, from Proto-Indo-European legʰ- — to lie.
Ancestry of “предположи́ть”, step by step
Words derived from “предположи́ть”