His niece is attractive and mature for her age. - Onun kız yeğeni çekici ve yaşına göre olgundur.
Tom has three nieces. - Tom'un üç kız yeğeni var.
A daughter of someone’s sibling, brother-in-law, or sister-in-law; either the daughter of one's brother ("fraternal niece"), or of one's sister ("sororal niece")
A relative, in general; especially, a descendant, whether male or female; a granddaughter or a grandson
Someone's niece is the daughter of their sister or brother. his niece from America, the daughter of his eldest sister. the daughter of your brother or sister, or the daughter of your wife's or husband's brother or sister nephew, aunt aunt, uncle uncle (neptia )