Origin and history of ash

"powdery remains of fire," Middle English asshe, from Old English æsce "ash," from Proto-Germanic *askon (source also of Old Norse and Swedish aska, Old High German asca, German asche, Middle Dutch asche, Gothic azgo "ashes"), from PIE root *as- "to burn, glow." Spanish and Portuguese ascua "red-hot coal" are Germanic loan-words.

The meaning "finely pulverized lava thrown from a volcano" is from 1660s. An ancient symbol of grief or repentance; hence Ash Wednesday (c. 1300, in Middle English also sometimes Pulver-wednesdai), from the custom introduced by Pope Gregory the Great of sprinkling ashes on the heads of penitents on the first day of Lent.

Ashes "mortal remains of a person" is attested from late 13c., in reference to the ancient custom of cremation.

popular name of a common type of forest tree of Eurasia, North America, and North Africa, Middle English asshe, from Old English æsc "ash tree," from Proto-Germanic *askaz, *askiz (source also of Old Norse askr, Old Saxon ask, Middle Dutch esce, German Esche), from PIE root *os- "ash tree" (source also of Armenian haci "ash tree," Albanian ah "beech," Greek oxya "beech," Latin ornus "wild mountain ash," Russian jasen, Lithuanian uosis "ash").

The close-grained wood of the ash is tough and elastic, and it was the preferred wood for spear-shafts, so Old English æsc sometimes meant "spear," especially in poetry, as in æsc-here "company armed with spears," æsc-plega "war," literally "spear-play." Æsc also was the name of the Old English runic letter that begins the word.