Where does “Рим” come from?

Рим (Bulgarian) comes from Old Church Slavonic Римъ, from Proto-Slavic Rimъ, from Latin Rōma — Rome and/or Constantinople (the latter as "Nova Roma").

Ancestry of “Рим”, step by step

Step	Language	Word	Meaning
1	Old Church Slavonic	Римъ	—
2	Proto-Slavic	Rimъ	Rome
3	Latin	Rōma	Rome and/or Constantinople (the latter as "Nova Roma")

Every word from Latin Rōma →Every word from Proto-Slavic Rimъ →Every word from Old Church Slavonic Римъ →