Etiquette is a set of rules for general politeness. As was put down in 1998: “Blowing one’s nose..is..set within a taken-for-granted set of social procedures and etiquette.” As you can probably tell from the spelling, “etiquette” entered English from French, and not that long ago as words go — probably in the early 1700s. But the word has a pretty convoluted history, and some meanings you might not expect.
In the 1300s and 1400s in France, “etiquette” meant two different things, and neither of them had anything to do with manners. It meant a label attached to something, and it also was a goalpost or target in a game.
The word originally came from the Old French “estiquette,” which meant a post in the ground. Why might you stick a post in the ground? Maybe to attach a sign! That’s where “etiquette” came from, and why it meant a label. In French, that’s what it still means; an “etiquette” is a price tag.
But by the 1500s, “etiquette” was used for a very particular sort of sign or label: the schedule of a royal person. It was first used this way in the court of Philippe the Good, also known as the Duke of Bourgogne. Over the next decades, “etiquette” came to mean not just the schedule, but the ceremonies in a noble court. In other words, the rules you had to follow in order to “mind your manners.” France was the European leader in fancy courts and their complex rules, so “etiquette” was adopted into several other languages, eventually including English.
But “etiquette” was already part of English by then. A couple of centuries before “etiquette” entered English to mean behavior, the older version of “etiquette” had entered English as “ticket,” and it meant something like a label. Just to make things more tangled, the word “ticket” eventually jumped from English back into French, where it’s used to mean a ticket like a bus ticket. And just for good measure, remember that “etiquette” originally meant some sort of sign or label, and “label” was also adopted into French, where it’s used to mean the kind of designation you apply to indicate approval or certification, like a “label de qualité.”
Luckily it’s apparently considered good language etiquette to borrow liberally from neighboring languages — you might say that’s the ticket.