יָבַם yâbam

Hebrew · Strong's H2992 · pronounced yaw-bam' · used 3 times in 3 verses

Meaning

to marry a (deceased) brother's widow

In the King James Version: perform the duty of a husband's brother, marry.

Derivation: a primitive root of doubtful meaning; used only as a denominative from H2993 (יָבָם);

Genesis 38:8 Then Judah said to Onan, “Sleep with your brother’s wife. Perform your duty as her brother-in-law and raise up offspring for your brother.”
Deuteronomy 25:5 When brothers dwell together and one of them dies without a son, the widow must not marry outside the family. Her husband’s brother is to take her as his wife and fulfill the duty of a brother-in-law for her.
Deuteronomy 25:7 But if the man does not want to marry his brother’s widow, she is to go to the elders at the city gate and say, “My husband’s brother refuses to preserve his brother’s name in Israel. He is not willing to perform the duty of a brother-in-law for me.”