Origins
Friday is the day of love — or more precisely, the day of the love-goddess, whether one calls her Venus, Frigg, or Freyja. The word's etymology opens a window onto both the systematic way Germanic peoples translated the Roman planetary week and one of the most debated questions in Norse mythology: the relationship between the goddesses Frigg and Freyja.
The word derives from Old English 'frīgedæg,' a compound of 'frīge' (genitive of 'Frīg,' the goddess) and 'dæg' (day). This was a calque of Latin 'Veneris diēs' (day of Venus), with the Germanic love-goddess substituted for the Roman one through interpretatio germanica. The equation was straightforward: Venus was the Roman goddess of love, beauty, and fertility; Frīg (Frigg) was the Germanic goddess of marriage, love, and the domestic sphere. Both were queens of their respective pantheons — Venus as the most beautiful of the Olympians, Frigg as the wife of Odin and queen of Asgard.
The Proto-Germanic name *Frijjō derives from the root *frijōną (to love), which in turn descends from PIE *preyH- (to love, to please). This root also produced Sanskrit 'priyá' (beloved, dear), Old Church Slavonic 'prijati' (to be favorable), and — through Germanic — the English words 'free' (originally meaning 'dear, beloved,' then 'belonging to the household,' then 'not enslaved') and 'friend' (from Old English 'frēond,' literally 'one who loves'). The web of connections is remarkable: Friday, free, and friend all ultimately derive from the same Indo-European root meaning 'to love.'
Old English Period
The question of whether 'Friday' honors Frigg, Freyja, or a conflation of both is one of the enduring puzzles of Germanic studies. In the Norse sources — which were written down centuries after the Old English period — Frigg and Freyja are clearly distinct goddesses. Frigg is Odin's wife, queen of the Æsir, associated with marriage, motherhood, and foreknowledge. Freyja is a Vanir goddess, associated with erotic love, war, magic (seiðr), and the afterlife. Yet many scholars have argued that in the older, common Germanic period, these two figures were a single goddess who later split into two in Scandinavian tradition. The Old English 'Frīg' may represent this undivided figure, or it may specifically correspond to Norse Frigg. The evidence is genuinely ambiguous.
The cognate forms across Germanic are consistent: German 'Freitag,' Dutch 'vrijdag,' Swedish 'fredag,' Danish 'fredag,' Norwegian 'fredag,' and Icelandic 'föstudagur' (fasting day, a Christian replacement). All the non-Icelandic forms transparently preserve the goddess's name.
In the Romance languages, the Latin 'Veneris diēs' produced French 'vendredi,' Spanish 'viernes,' Italian 'venerdì,' and Romanian 'vineri' — all preserving Venus. Portuguese 'sexta-feira' (sixth fair/day) again uses the ecclesiastical numbering system.
Latin Roots
Friday has accumulated a rich and contradictory cultural mythology. In Christianity, Friday is the day of the Crucifixion and has traditionally been observed with fasting and abstinence — hence the Catholic tradition of eating fish on Fridays and the Icelandic replacement name 'föstudagur' (fasting day). Yet in Norse and broader Germanic tradition, the love-goddess's day was auspicious for weddings and romantic endeavors. These two traditions collided to produce the peculiarly English superstition that Friday is unlucky — a belief that appears to derive from the Christian association with the Crucifixion rather than from any Germanic precedent.
The specific superstition of Friday the 13th being unlucky is surprisingly recent. Despite popular claims tracing it to the arrest of the Knights Templar on Friday, October 13, 1307, there is no documented evidence of the combined Friday-plus-thirteen superstition before the nineteenth century. The earliest known reference appears in an 1869 biography of the composer Gioachino Rossini, who died on Friday, November 13, 1868. The superstition appears to have crystallized from two separate traditions — Friday as unlucky and thirteen as unlucky — merging into a single potent anxiety only in the modern era.
In modern English, Friday has been thoroughly rehabilitated from its medieval unluckiness. 'TGIF' (Thank God It's Friday) captures the contemporary secular meaning: Friday as liberation, the gateway to the weekend, the day when the working week ends and leisure begins — a meaning that would have baffled medieval Christians for whom Friday meant penance, and ancient Germanic peoples for whom it meant love.