The son of one's sister.

The son of one's brother.

The son of someone's stepbrother or stepsister. / The stepson of someone's brother or sister.

son of one's half brother or half sister

Alternative spelling of half nephew

plural of sororal nephew

plural of fraternal nephew

plural of step-nephew

(anthropology) The son of one's sister.

(vulgar) Motherfucker (generic term of abuse).