A nephew is a son of one's sibling or half-sibling, and a niece is a daughter of one's sibling or half-sibling. Sons and daughters of siblings-in-law are also referred to as nephews and nieces respectively, even though there is no blood relation. The word nephew is derived from the French word neveu.

• Nephew – son of one's brother/sister (and his/her spouse).
• Niece – daughter of one's sister/brother (and her/his spouse).
• Nibling – uncommon gender-neutral term for niece or nephew.^[1]
• Half-nephew – son of one's half-brother/half-sister.
• Half-niece – daughter of one's half-brother/half-sister.
• Nephew-in-law – son of one's sister-in-law/brother-in-law; husband of one's niece.
• Niece-in-law – daughter of one's sister-in-law/brother-in-law; wife of one's nephew.
• Step-nephew – son of one's stepbrother/sister, or stepson of one's brother/sister.
• Step-niece – daughter of one's stepbrother/sister, or stepdaughter of one's brother/sister.
• Half-nephew-in-law – son of one's wife/husband's half-brother/half-sister; husband of one's half-niece.
• Half-niece-in-law – daughter of one's wife/husband's half-brother/half-sister; wife of one's half-nephew.
• Step-nephew-in-law – son of one's wife/husband's stepbrother/stepsister; husband of one's step-niece.
• Step-niece-in-law – daughter of one's wife/husband's stepbrother/stepsister; wife of one's step-nephew.
• Great-nephew (also called "grand nephew") – son of one's nephew/niece, grandson of one's sister/brother.
• Great-niece (also called "grand niece") – daughter of one's nephew/niece, granddaughter of one's sister/brother.
• Great-nephew-in-law (also called "grand nephew-in-law") – son of one's nephew/niece, grandson of one's sister-in-law/brother-in-law.
• Great-niece-in-law (also called "grand niece-in-law") – daughter of one's nephew/niece, granddaughter of one's sister-in-law/brother-in-law.
• Step-great-nephew – son of one's stepnephew/niece, or stepson of one's nephew/niece.
• Step-great-niece – daughter of one's stepnephew/niece, or stepdaughter of one's nephew/niece.
• Step-great-nephew-in-law – husband of one's step-great-niece.
• Step-great-niece-in-law – wife of one's step-great-nephew.
• Half-great-nephew – son of one's half-nephew/niece.
• Half-great-niece – daughter of one's half-nephew/niece.
• Half-great-nephew-in-law – husband of one's half-great-niece.
• Half-great-niece-in-law – wife of one's half-great-nephew.
• Cousin-nephew – son of one's first cousin (i.e., a first-cousin-once-removed who is male and in the younger generation).
• Cousin-niece – daughter of one's first cousin (i.e., a first-cousin-once-removed who is female and in the younger generation).

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