* Spanish
* Portuguese
* Italian
* Filipino
* Catalan
* Galician
It can refer to a sister of one's parent, or a close friend of the family who is considered like an aunt.
It's also worth noting that "Tia" can be a given name in some cultures.
If you're unsure about the context in which you encountered the word "Tia," providing more information will help me give you a more precise answer.