Ash is:

• The solid residue left after something has burned, usually wood and plant material (such as tobacco). It consists mainly of carbonates and bicarbonates of metals in the original organic material - the metals that primarily compose the ash of the analytical chemistry meaning.
• In analytical chemistry, ash is one of the components in the proximate analysis of biological materials.
• Rocky material ejected from a volcano; see Volcanic ash.
• A genus of trees (Fraxinus); see Ash tree.
• In Old English, a letter named after the tree; see Æ.
  • In the International Phonetic Alphabet, lowercase ash (æ) corresponds to the near-open front unrounded vowel.
• In Egyptian mythology, the hawk-god of the Sahara Desert; see As (god).
• The main hero of the Pokémon television series; see Ash Ketchum.
• The antihero of the Evil Dead trilogy is named Ash Williams.
• A Britpop band; see Ash (band).
• One of the Unix shells that serves as a command-line interface for computers running some variants of the Unix operating system; see Almquist shell.
• In the compound form Mountain-ash, two other trees; Eucalyptus regnans in Australia, and an old alternative name for Rowans (Sorbus species).
• A common short form for alt.suicide.holiday, a Usenet newsgroup

Ash is also the name of several places in the United Kingdom:

• Ash, New Ash Green, Kent , England
• Ash-next-Sandwich, Kent, England
• Ash, Somerset , England
• Ash, Surrey , England