"Rent Temporarily" with a comment "Rent can be terminated by renter at any time, without ability to appeal". Because "rent indefinitely" is definitely incorrect since it is impossible.
This is a similar misconception to the word "infinite", which many people believe means "an unending amount" but actually just means "not finite"; an amount large enough that it can't be quantified, but still an amount nonetheless. This comes into play in mathematics when talking about some infinities being larger than others.
If you take a nihilistic view of the universe, then everything is temporary, and thus even the DVDs you've purchased should have been advertised as a temporary rental. That's not very useful, though.