Tiptronic is a Porsche trademark for an automatic transmission with manual override, which has become a generic name for any similar transmission.
The Tiptronic system uses a conventional automatic gearbox with torque converter and adds manual control using a secondary gear selection gate with + and - positions which shift up or down.
Choose a letter from the Jargonbuster
Choose from above to see the list of jargon for that letter,
or see the full Jargonbuster list here