The definition of niece is the daughter of your brother or sister, by blood or by marriage.
A species or other taxon that shares a common ancestor, usually a relatively recent ancestor, with another:
A son of one's nephew or niece.
Find another word for nephew. In this page you can discover 22 synonyms, antonyms, idiomatic expressions, and related words for nephew, like: brother's son, niece, relative, son of a brother-in-law, grandnephew, son of a sister-in-law, nephew by marriage, sister's son, grandson, brother-in-law and son.