nephew
n. countablen. the son of your brother or sister. You also use this word for the son of your husband's or wife's sibling.
n. a male child of one's sibling or sibling-in-law. The term identifies a specific kinship relation within the extended family structure.
I am taking my nephew to the park for his birthday.
She bought a new bicycle for her nephew when he finally learned how to ride without training wheels.
Although they lived in different countries, he maintained a close relationship with his nephew through weekly video calls and annual summer visits.
From Middle English nevew, neveu (“nephew, grandson”), from Old French neveu, from Latin nepos, nepōtem, from Proto-Italic nepōts (“nephew, grandson”), whence also French neveu, Italian nipote. Displaced or absorbed the inherited English neve (“nephew, grandson, male cousin”), from Middle English neve, from Old English nefa, from Proto-West Germanic nefō, from Proto-Germanic nefô (“nephew, grandson”), whence Dutch neef, German Neffe. All ultimately from Proto-Indo-European népōts (“grandchild, sister's son”). Cognate with Serbo-Croatian nećak, Irish nia, Persian نوه (nave). Spelt with -ph- by readaptation to Latin nepos since the 15th century, which later triggered the spelling pronunciation with /f/.
The female equivalent is 'niece'.