The Old Norse word eisa
Word eisa
e i s a
Meaning fire
Synonyms eldr

Other words that might be of interest
aska ‘ashes’, skírr ‘clear, bright’, døkkr ‘dark’, dimmar ‘dark, gloomy’, myrkr ‘dark, murky’, dimma ‘darkness’, logi ‘flame, blaze’, heitr ‘hot, burning’, skuggi ‘shadow’, reykr ‘smoke, steam’, sól ‘sun’, sunna ‘sun’