A custom of the Jews in Biblical times by which a dead man's brother was obligated to marry the widow if there were no sons: Deut. 25:5-10
(countable) A marriage between a widow and her deceased husband's brother or, sometimes, heir.
The practice of marrying the widow of one's childless brother to maintain his line, as required by ancient Hebrew law.
(anthropology) The institution of levirate marriage.