Jera (also Jeran, Jeraz) is the conventional name of the j-rune ᛃ of the Elder Futhark, from a reconstructed Common Germanic stem **jēra-*^[1] meaning "harvest, (good) year".

The corresponding letter of the Gothic alphabet is Gothic 𐌾, named 𐌾𐌴𐍂 (jēr), also expressing /j/. The Elder Futhark rune gives rise to the Anglo-Frisian runes ᛄ /j/, named gēr /jeːr/, and ᛡ /io/, named ior, and to the Younger Futhark ár rune ᛅ, which stood for /a/ as the /j/ phoneme had disappeared in Old Norse.

Note that ᛆ also can be a variation of dotted Isaz used for /e/; e.g. in Dalecarlian runes.

The reconstructed Common Germanic name *jēran is the origin of English year (Old English ġēar). In contrast to the modern word, it had a meaning of "season" and specifically "harvest", and hence "plenty, prosperity".

The Germanic word is cognate with Greek ὧρος (horos) "year" (and ὥρα (hora) "season", whence hour), Old East Slavic ꙗра (jara) "spring" and with the -or- in Latin hōrnus "of this year" (from hōjōrō), as well as Avestan 𐬫𐬁𐬭𐬆 (yārə) "year", all from a PIE stem **yer-o-.

The derivation of the rune is uncertain; some scholars see it as a modification of Latin G ("C (ᚲ) with stroke") while others consider it a Germanic innovation. The letter in any case appears from the very earliest runic inscriptions, figuring on the Vimose comb inscription, harja.

As the only rune of the Elder Futhark which was not connected, its evolution was the most thorough transformation of all runes, and it was to have numerous graphical variants.^[2] In the later period of the Elder Futhark, during the 5th to 6th centuries, connected variants appear, and these are the ones that give rise to the derivations in Anglo-Saxon (as ᛄ ger and ᛡ ior) and Scandinavian (as ᛅ ár) traditions.

The corresponding Gothic letter is 𐌾 (j), named jēr, which is also based on the shape of the Elder Futhark rune. This is an exception, shared with urus, due to the fact that neither the Latin nor the Greek alphabets at the time of the introduction of the Gothic one had graphemes corresponding to the distinction of j and w from i and u.

The rune in the futhorc is continued as gēr, with its epigraphical variant ᛡ, and its manuscript variant ᛄ (which does appear once epigraphically, on the Brandon Pin). Manuscripts also record an ior rune with the shape of ᛡ, but its authenticity is questionable.^[3]

During the 7th and 8th centuries, the initial j in *jara was lost in Old Norse, which also changed the sound value of the rune from /j/ to an /a/ phoneme. The rune was then written as a vertical staff with a horizontal stroke in the centre, and scholars transliterate this form of the rune as A, with majuscule, to distinguish it from the ansuz rune, a.

During the last phase of the Elder Futhark, the jēra-rune came to be written as a vertical staff with two slanting strokes in the form of an X in its centre ([[INLINE_IMAGE|//upload.wikimedia.org/wikipedia/commons/thumb/5/52/H-rune.png/10px-H-rune.png|//upload.wikimedia.org/wikipedia/commons/thumb/5/52/H-rune.png/15px-H-rune.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/52/H-rune.png/20px-H-rune.png 2x|H-rune.png|h13|w10]]). As the form of the rune had changed considerably, an older 7th century form of the rune ([[INLINE_IMAGE|//upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Long-branch_Sol.png/6px-Long-branch_Sol.png|//upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Long-branch_Sol.png/9px-Long-branch_Sol.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Long-branch_Sol.png/12px-Long-branch_Sol.png 2x|Long-branch Sol.png|h12|w6]]) was assumed by the s-rune.^[2] When the n-rune had stabilized in its form during the 6th and 7th centuries, its vertical stroke slanted towards the right ([[INLINE_IMAGE|//upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Runic_letter_naudiz.svg/10px-Runic_letter_naudiz.svg.png|//upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Runic_letter_naudiz.svg/15px-Runic_letter_naudiz.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Runic_letter_naudiz.svg/20px-Runic_letter_naudiz.svg.png 2x|Runic letter naudiz.svg|h25|w10]]), which made it possible to simplify the jēra-rune by having only one vertical stroke that slanted towards the left, giving the ᛅ ár-rune of the Younger Futhark. Since a simpler form of the rune was available for the /a/ phoneme, the older cross form of the rune now came to be used for the /h/ phoneme.^[4]

The development of the Jēran rune from the earliest open form was not known before the discovery of the Kylver Stone in 1903, which has an entire elder futhark inscription on it. Therefore, the interpretation of the golden horns of Gallehus was slightly wrong before 1903, as it was believed this rune form could be an early form of the Ingwaz rune. The second word on the horns was thus interpreted as holtingaz rather than holtijaz.^[5]