Tia is the Spanish and Portuguese word for "aunt" — also used as a 20th-century American given name (often a diminutive of names ending in -tia such as Letitia). Tia Leoni is Téa (different name). "Tia" is also the Polynesian-Maori word for "sacred space" — Tia Reed Maoris, Tia and Piujuq (Inuit/Tunisian short film).
Subject of countless 1990s sitcom retrospectives.
Tia does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Tia reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.