That's not true. Rendition is the act a host country takes in yielding a subject to the country requesting extradition.

What you're referring to is the Orwellian term "extraordinary rendition" (the correct term is "kidnapping"), in which subjects are detained extrajudicially and shipped to a third party jurisdiction to be tortured. "Torture" is important to the definition of "extraordinary rendition", as getting subjects to countries where they can be tortured is the reason "extraordinary" measures have to be taken in the first place.