Wiktionary
nephew-in-law
n. 1 son-in-law of someone's brother. (''fraternal nephew-in-law'') 2 son-in-law of someone's sister. (''sororal nephew-in-law'') 3 Son-in-law of someone's brother-in-law. 4 Son-in-law of someone's sister-in-law. 5 ''Rare.'' Nephew of someone's husband. (Usually called a ''nephew'') 6 ''Rare.'' Nephew of someone's wife. (Usually called a ''nephew'') 7 Husband of someone's niece.
Usage examples of "nephew-in-law".
Vorthys finished wiping his mouth with his dinner napkin, stuffed it absently into his pocket, and greeted Tuomonen with a handshake, then introduced his nephew-in-law.