Quinceañera is the common English loanword for a girl celebrating her fifteenth birthday in this tradition.
In Spanish, quinceañera is a feminine noun formed from quince, meaning fifteen. It can identify the young woman being honored and, in everyday English, can also refer to the party itself. Context usually makes clear which meaning is intended.
The masculine counterpart is quinceañero, although the celebration is most strongly associated with girls and young women. English usage often keeps the original Spanish spelling, including the ñ. The word is widely used in the United States and in English-language writing about Latino cultures.
Not every family uses the same label. Quince, quince años, and fiesta de quince años are also common names for the event. These terms describe related customs rather than a single globally standardized ceremony.