Origins
The English word 'east' is, at its deepest level, a word about light. It descends from Old English 'ēast,' from Proto-Germanic *austrą, which traces to the Proto-Indo-European root *h₂ews-, meaning 'to shine' or 'to glow with the reddish light of dawn.' East is therefore 'the direction of the shining' — the quarter of the sky where the sun appears each morning.
The PIE root *h₂ews- is one of the most productive and well-attested roots in comparative linguistics. It generated dawn-words across the entire Indo-European family: Latin 'aurōra' (dawn, later the Roman goddess of dawn), Greek 'ēōs' (dawn, also personified as the goddess Eos), Sanskrit 'uṣas' (dawn, the Vedic goddess Ushas), and Lithuanian 'aušrà' (dawn). The consistency of both form and meaning across these widely separated branches provides strong evidence for the reconstruction.
Within Germanic, the root produced not only the directional word but also the name of a goddess. The Venerable Bede, writing in 725 CE in his 'De Temporum Ratione,' recorded that the Anglo-Saxon month roughly corresponding to April was called 'Ēosturmōnaþ,' named after a goddess called 'Ēostre.' Bede stated that feasts had formerly been held in her honor during that month, but that the tradition had been supplanted by the Christian celebration of the Resurrection, which nonetheless retained the old name. This is the origin of 'Easter' — the most important Christian holiday in English bears the name of a Germanic dawn-goddess.
Proto-Indo-European Roots
The connection between east, dawn, and divinity runs deep in Indo-European culture. The Vedic goddess Ushas is one of the most extensively hymned deities in the Rigveda, celebrated for her beauty and her daily act of driving away darkness. Greek Eos was imagined opening the gates of heaven each morning for the sun-chariot to emerge. The Roman Aurora performed the same mythological function. All these figures descend from a common PIE dawn-goddess, *H₂éwsōs, whose name is simply the personification of the root *h₂ews-.
The Germanic cognates follow regular sound correspondences: German 'Ost,' Dutch 'oost,' Old Norse 'austr,' and Old Frisian 'āst.' The word was borrowed into Romance languages as well — French 'est,' Italian 'est,' Spanish 'este' — displacing the Latin directional term 'oriēns' (rising, from 'orīrī,' to rise) in everyday use, though 'orient' survived as a learned English borrowing meaning 'the east' and gave us 'orientation' (literally, 'facing east').
The place-name legacy of 'east' is vast. Essex is 'east Saxons.' East Anglia is the 'eastern territory of the Angles.' Austria derives from Old High German 'Ostarrîchi' (eastern realm), Charlemagne's name for the frontier territory that became the Habsburg heartland. Even 'Australia' — coined from Latin 'australis' (southern) — is sometimes folk-etymologically connected to 'east,' though the actual derivation is from the Latin south-word.
Old English Period
The phonological history of 'east' in English is straightforward. Old English 'ēast' had a long /æː/ vowel (later /eː/), which the Great Vowel Shift raised to /iː/. The same shift affected 'beast' (from Old French, but with the same vowel), 'feast,' and 'least.' The spelling 'ea' for the /iː/ sound is a relic of the earlier pronunciation.
The metaphorical resonance of 'east' in English literature is profound. Because east is the direction of dawn, it has long been associated with hope, renewal, and beginnings. In Christian symbolism, churches are traditionally oriented with the altar at the east end, so that the congregation faces the direction of the rising sun — and of the anticipated Second Coming. The word 'orientation' preserves this practice: to orient a church was originally to align it eastward.