means A small piece of paper or its digital equivalent that grants entry, proves payment, reserves a spot, or—less happily—formally records a fine or offense.

from From the French étiquet, a little note or label stuck onto something (and yes, the very same root as 'etiquette,' which began as a posted list of rules at court). The French verb estiquier meant 'to stick' or 'attach,' likely borrowed from a Germanic source—a cousin of the modern 'stick.' English clipped off the front and kept 'ticket,' so the word still carries its first job in its bones: a tag stuck on to say who paid, who's allowed, or what the rules are.