Where does “Tolstoy” come from?

Tolstoy derives from Russian Толсто́й, the nominative singular form of Russian то́лстый meaning "thick" or "stout."

Ancestry of “Tolstoy”, step by step

Step	Language	Word	Meaning
1	Russian	Толсто́й	—
2	Russian	то́лстый	stout
3	Russian	-щина	—

Tolstoy — Etymology, Origin & Word History | Etymology Explorer