Ehwaz

*Ehwaz is the reconstructed Proto-Germanic name of the Elder Futhark e rune, meaning "horse" (cognate to Latin equus, Gaulish epos, Tocharian B yakwe, Sanskrit , Avestan and Old Irish ech). In the Anglo-Saxon futhorc, it is continued as eh (properly eoh, but spelled without the diphthong to avoid confusion with  ēoh "yew").

The Proto-Germanic vowel system was asymmetric and unstable. The difference between the long vowels expressed by e and  ï (sometimes transcribed as *ē1 and *ē2) was lost. The Younger Futhark continues neither, lacking a letter expressing e altogether. The Anglo-Saxon futhorc faithfully preserved all Elder futhorc staves, but assigned new sound values to the redundant ones, futhorc ēoh expressing a diphthong.

In the case of the Gothic alphabet, where the names of the runes were re-applied to letters derived from the Greek alphabet, the letter 𐌴 e was named "horse" as well (note that in Gothic orthography, $⟨aí⟩$ represents monophthongic /e/).

The rune may have been an original innovation, or it may have been adapted from the classical Latin alphabet's E.

Anglo-Saxon rune poem
The Anglo-Saxon rune poem has:
 * Eh bẏþ for eorlum æþelinga ƿẏn,
 * hors hofum ƿlanc, ðær him hæleþ ẏmb[e]
 * ƿelege on ƿicgum ƿrixlaþ spræce
 * and biþ unstẏllum æfre frofur.


 * "The horse is a joy to princes in the presence of warriors.
 * A steed in the pride of its hoofs,
 * when rich men on horseback bandy words about it;
 * and it is ever a source of comfort to the restless."