In Western culture, the custom of a newlywed couple going on a holiday together originated in early 19th century Great Britain. Upper-class couples would take a "bridal tour", sometimes accompanied by friends or family, to visit relatives that had not been able to attend the wedding. The practice soon spread to the European continent and was known as voyage à la façon anglaise (English-style voyage) in France from the 1820s on.
Honeymoons in the modern sense (i.e. a pure holiday voyage undertaken by the married couple) became widespread during the Belle Époque, as one of the first instances of modern mass tourism. This came about in spite of initial disapproval by contemporary medical opinion (which worried about women's frail health) and by savoir vivre guidebooks (which deplored the public attention drawn to what was assumed to be the wife's sexual initiation). The most popular honeymoon destinations at the time were the Côte d'Azur and Italy, particularly its seaside resorts and romantic cities such as Rome, Verona or Venice.
The Oxford English Dictionary offers no etymology, but gives examples dating back to the 16th century. The Merriam-Webster dictionary reports the etymology as from "the idea that the first month of marriage is the sweetest" (1546).
A honeymoon can also be the first moments a newly-wed couple spend together, or the first holiday they spend together to celebrate their marriage.
The first month after marriage, when there is nothing but tenderness and pleasure" (Samuel Johnson); originally having no reference to the period of a month, but comparing the mutual affection of newly-married persons to the changing moon which is no sooner full than it begins to wane; now, usually, the holiday spent together by a newly-married couple, before settling down at home.
One of the more recent citations in the Oxford English Dictionary indicates that, while today honeymoon has a positive meaning, the word was originally a reference to the inevitable waning of love like a phase of the moon. This, the first known literary reference to the honeymoon, was penned in 1552, in Richard Huloet's Abecedarium Anglico Latinum. Huloet writes:
Hony mone, a term proverbially applied to such as be newly married, which will not fall out at the first, but th'one loveth the other at the beginning exceedingly, the likelihood of their exceadinge love appearing to aswage, ye which time the vulgar people call the hony mone.
In many parts of Europe it was traditional to supply a newly married couple with enough mead for a month, ensuring happiness and fertility. From this practice we get honeymoon or, as the French say, lune de miel
There are many calques of the word honeymoon from English into other languages. The Welsh word for honeymoon is mis mêl (honey month). In Hebrew it is 'Yerach D'vash translated to honey month (interestingly the word 'Yerach'-Month is very close to the word 'Yare'ach'-Moon. The two words are spelled alike: ירח). In Arabic it is shahr el 'assal also translated to honey month. The Spanish word for honeymoon is la luna de miel (the moon of honey), and the Italian luna di miele (same translation). The Persian word for it is mah e asal which has both the translations honeymoon and honey month (mah in Persian meaning both moon and month).