The Old Norse word aska
Word aska
a s k a
Meaning ashes
See also Hittite: ḫa-a-aš ‘ashes, dust, soap’

Other words that might be of interest
eisa ‘fire’, eldr ‘fire’, 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’