The young woman being honored at the celebration is called the quinceañera.
In Spanish usage, quinceañera can identify the celebrant as well as the celebration itself. The word is related to quince, “fifteen,” and traditionally refers to a girl or young woman marking her fifteenth birthday through a formal family and community event.
English-language writing often uses quinceañera as the name of the party, which is understandable because the term has become an established loanword. In Spanish, however, context may determine whether it means the person or the occasion. The phrase fiesta de quince años makes the event meaning explicit.
The tradition has changed over time and differs by community. Contemporary quinceañeras may be religious, secular, elaborate, intimate, conventional, or highly personalized. The term identifies the celebrant, but it does not prescribe one universal ceremony or set of behaviors.