D defs.my
Entry 1 sense Webster, 1913

Levirate

/(lĕv"ĭ*rā̇t)/ · Lev·i·rate · IPA /ˈlɛvɪɹət/
01 a. Of, pertaining to, or in accordance with, a law of the ancient Israelites and other tribes and races, according to which a woman, whose hus…
  1. 1.
    Of, pertaining to, or in accordance with, a law of the ancient Israelites and other tribes and races, according to which a woman, whose husband died without issue, was married to the husband's brother.
    “The firstborn son of a leviratical marriage was reckoned and registered as the son of the deceased brother.” — Alford.