A ceremony named for a pledge
In everyday English a wedding is the public rite that starts a marriage: the service or legal act, and often the gathering that follows. The related verb wed still means to marry, though it now sounds a little more formal or literary than marry itself. The origin of the word wedding is not a tale of church Latin or of French nuptials. It is a native English story about making a pledge.
An Old English verbal noun
Wedding is formed inside English. Historical dictionaries treat it as a derivation: the verb wed plus the familiar noun-forming suffix that in Old English appeared as -ung or -ing. The Old English noun was weddung. Before 1150 it already named the state of being wed, a pledge or betrothal, and the act of marrying. Middle English kept the same stem, with spellings such as weddynge and weddyng, before the modern form settled.
The verb behind it, Old English weddian, was broader than our wed. It could mean to pledge oneself, to make a covenant, to vow, to betroth, and to marry. A priest could weddian a couple in the sense of joining them. The oldest marital use described a man taking a woman as wife by giving a pledge or earnest; later the verb applied to either party. From about 1200 people could be said, in the passive, to be joined as husband and wife. Direct use of the verb of a woman marrying is later, from the late fourteenth century. In Middle English wedden could still mean to wager, a reminder that the marital sense had not yet monopolized the word. In parts of northern England and in Scots that wagering sense of wed has not entirely died.
This is inheritance, not borrowing. English did not import wedding from French mariage or Latin nuptiae. Those words exist beside it, but the stem is Germanic and already English in the Old English period.
Pledge, wager, and a disputed deeper root
Old English also had a noun wedd, a pledge, security, or covenant. The verb and the noun sit on the same Germanic stock. Comparative reconstruction gives Proto-Germanic *wadjōną, to wager or pledge, from a noun *wadją, a pledge or stake. Cognates across the family still cluster around betting and promising: Old Norse veðja, Danish vædde, Dutch wedden, German wetten, Old Frisian weddia to promise, Gothic gawadjōn to betroth, Icelandic veðja, and Swedish vädja in the related sense of appealing. German Wette still means a bet.
How far back the root goes is less settled. One common reconstruction takes a Proto-Indo-European form meaning to pledge or to redeem a pledge, with Latin vas, vadis (bail or security) and Lithuanian vaduoti (to redeem a pledge) as outside relatives. Handbooks disagree on the exact shape of that ancestral form. The Germanic specialist Boutkan accepts the Germanic set but suspects a substrate origin rather than a tidy Indo-European pedigree. The honest position is that the Germanic pledge-word is secure; the exact prehistory is not.
A later, roundabout family of English words belongs here too. Frankish or other Germanic speech passed the same *wadja- into Old French, where an initial w often became g. From that detour English received gage, wage, wager, engage, and mortgage, the last a death-pledge in its French makeup. So wedding and engagement, which now sit next to each other in the same social script, are historically cousins: one stayed in English, the other came back through French.
When the name attached to the ceremony
The meaning nuptials, the ceremony of marriage, is recorded from the early thirteenth century. That is a narrowing. In Old English, weddung could still be the pledge or the betrothal as much as the marrying. For the ceremony itself speakers had other words. One was bridelope, literally a bridal run, referring to conducting the bride to her new home. Another was wif-þing, a wife-assembly, using thing in its old sense of a meeting rather than an object.
English is unusual in having specialized this pledge-root for marriage. Elsewhere in Germanic the descendants mostly stayed with wagering. That split is worth keeping in view: a wedding in English is not etymologically a feast or a holy union. It is, at bottom, the named act of giving security.
Compounds show how the ceremony sense then filled everyday life. Wedding ring is late fourteenth century. Wedding day is by the 1550s; a little earlier, in the mid-fifteenth century, wedding-daies could mean the days around the event. Wedding cake is recorded from the 1640s, wedding dress from 1779, wedding reception from 1856. A figurative use of wed, to join closely in affection, appears by 1818, and wedding itself can still mean a joining of parts or institutions, not only of people.
The takeaway in a German wager
If you want a single check on the history, look at German Wette. Same family, different job: a bet. English alone took the old pledge-verb and made it the ordinary name for marrying, then built wedding as the noun for the day. The flowers and the cake came later. The legal earnest came first.