A life estate is a freehold estate that is of limited duration, continuing only for the
duration of the life of a person named (the measuring life). There are two types of life
estates: a life estate for the life of the tenant, and a life estate for the life of another
person (pur autre vie).

Un intérêt viager est un domaine franc d’une durée limitée, qui se poursuit uniquement
pendant la durée de la vie de la personne nommée (la vie-mesure). Il y a deux types
d’intérêts viagers : l’intérêt viager pour la vie du tenant, et l’intérêt viager pour la vie d’une
autre personne (domaine à vie d’autrui)."
Life Estates and Land Titles Intérêt viager et titre foncier
https://www.pxw1.snb.ca/snb7001/e/PDF/News2014-05-E.pd

"Rentier
signifie la ou les personnes au décès de laquelle ou
desquelles le capital-décès est payable, après quoi le contrat et toute
garantie applicable s’y rattachant prennent fin. Il s’agit de la ou des
personnes dont le ou les noms figurent en tant que «
proposant
»
sur une proposition acceptée par la Compagnie, sauf indication
contraire sur ladite proposition. Pour les besoins du calcul du capital-
décès, du pourcentage de retrait de la GRV et de toutes les autres
garanties, la vie-mesure est celle du rentier le plus jeune. Dans le cas
où plus d’une personne est désignée comme rentier, le capital-décès
est payable et toute autre garantie prend fin au décès du dernier
survivant. Le rentier ne peut pas être remplacé sans le consentement
de la Compagnie. En ce qui a trait à tous les régimes enregistrés, le
rentier est toujours le titulaire du contra"
https://docplayer.fr/5407669-Contrat-et-notice-explicative.h...

"The ownership of a life estate is of limited duration because it ends at the death of a person. Its owner is the life tenant (typically also the 'measuring life') and it carries with it right to enjoy certain benefits of ownership of the property, chiefly income derived from rent or other uses of the property and the right of occupation, during his or her possession. Because a life estate ceases to exist at the death of the measuring person's life, the life tenant, a temporary owner, may short-term let but cannot sell, give or bequeath the property indefinitely (including assuming it could pass to heirs (intestate)) or creating a purported document leaving it to devisees (testate). "
https://en.wikipedia.org/wiki/Life_estate

"A life estate is an interest in land whose duration is measured by a human life. The holder has the right to possess the property as long as he or she lives. At the death of the holder, the property reverts back to the owner.

Most often, as in the life estate discusses in the last example the “measuring life” will be that of the recipient. However, this need not be the case. A life estate can be measured by any life in existence at the time that the interest is created. A life estate that is not measured by the life of the holder is known as a life estate pur autre vie (“for the life of another”). If no life is specifically mentioned in the creation of the life estate, the measuring life is presumed to be the life of the recipient. For example:

John gives an acre of land “to Mary for life.” Mary has a life estate. She has an interest in the land that lasts as long as she lives and the interest will end when she dies.
John gives an acre of land “to Mary for the life of Chris.” Mary has a life estate pur autre vie, which is measured by Chris’ life. She has an interest in the land that lasts as long as Chris lives and the interest will end when Chris dies. Note that if Mary dies before Chris, her heirs will take over the land for as long as Chris continues to live."
https://lawshelf.com/courseware/entry/the-life-estate