from
The Collaborative International Dictionary of English v.0.48
Levirate \Lev"i*rate\ (l[e^]v"[i^]*r[asl]t), Leviratical
\Lev`i*rat"ic*al\ (-r[a^]t"[i^]*kal), a. [L. levir a husband's
brother, brother-in-law; akin to Gr. dah`r: cf. F. l['e]virat
leviration.]
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.
[1913 Webster]
The firstborn son of a leviratical marriage was
reckoned and registered as the son of the deceased
brother. --Alford.
[1913 Webster]