Answer:
It endures over the lifetime of a third person, after which the property passes from the tenant holder to the original grantor
Explanation:
"Pur autre vie" is a French phrase which refers to "for another's life". In such cases, the grantor passes on a property to a party, the duration of which is dependent on the life of a third person.
Upon the demise of such a third party, the estate in such a property gets reverted to the original grantor.
For example, A grants an estate in property to B, the duration of which is limited till the lifetime of C. In the event of C's death, the property reverts back to A i.e the original grantor.