The girl or young woman being honored at a quinceañera is called the quinceañera. The same word is also widely used in English to describe the celebration itself, which can create two overlapping meanings.
In Spanish, the feminine ending identifies the female honoree. The party may instead be called a fiesta de quince años or quince años. Families and communities may use these terms differently, but quinceañera is the most internationally recognizable label.
The honoree is typically the central figure in the ceremony and reception. She may enter formally, participate in a religious service, receive symbolic gifts, dance with a parent, and lead a court presentation. None of those elements is mandatory in every family’s version.
Quinceañera should not be confused with madrina, which commonly means a female sponsor or godmother, or with dama, a female member of the court. Chambelán usually refers to a male escort or court member. Those are roles around the honoree, not names for the honoree herself.