са́жа • (sáža) f inan (genitive са́жи, nominative plural са́жи, genitive plural саж)
From Proto-Slavic *saďa, cognate with Bulgarian сажди (saždi), Čakavian Serbo-Croatian sađa and saže, Slovene saje, Slovak sadza. Non-Slavic cognates include Old Norse sót (“soot”).