Any device that connects to the computer, such as a printer, scanner, monitor, keyboard or mouse.
No, the USB is not for connecting to the TV. That's for viewing photos from a USB thumb drive. She'll need an HDMI connection, but her Dell Latitude doesn't have an HDMI out. Many laptops will have VGA out, and it's possible that her TV has a VGA input. This would work, but it isn't the best way to connect it because it's analog, not digital. Her laptop does have DisplayPort for video, though.