The female Terminator in Terminator 3: Rise of the Machines is designated the T-X.
The T-X is portrayed by Kristanna Loken and serves as the primary machine antagonist of the 2003 film. It is sent from the future to eliminate key members of the human resistance, including John Connor and Kate Brewster.
The T-X combines a solid endoskeleton with a liquid-metal outer body. It can imitate appearances and form weapons, while also carrying specialized equipment intended to control or destroy other machines. This design makes it different from both the earlier T-800 and the liquid-metal T-1000.
The name is sometimes written as “TX” in informal references, but “T-X” is the film’s standard designation. The character is also known as the Terminatrix in some promotional and reference material.