Ash
Ashes
noun
The kanji and the word are exactly the same. That means they share meanings as well.
The reading is the same as the one you learned with the kanji.
鹿児島の桜島の火山の噴火で、近くの街は灰だらけになってしまいました。
The Sakurajima volcano eruption in Kagoshima covered the nearby city with ash.