In a quinceañera, “quinceañera” is the Spanish word for the honored girl’s fifteenth-birthday celebration.
The term is feminine because it refers both to the celebration and, in common usage, to the girl being honored. It is formed from quince, meaning fifteen, and años, meaning years, with the Spanish feminine ending associated with the tradition.
English-language usage often keeps the Spanish word, especially in communities with Latin American heritage. Spelling and accents matter: quinceañera includes the letter ñ, although “quinceanera” is also frequently written without the diacritic in English-language contexts.
The related masculine word quinceañero can refer to a boy’s fifteenth-birthday celebration or the boy being honored. That form is less common internationally because the quinceañera tradition has historically centered on girls.