Niece

n. daughter of one's brother or sister

A cousin in English kinship terminology is a relative with whom one shares a common grandparent or more distant ancestor, and who is not in one's own line of descent. The term cousin never applies where there are other specific terms to describe relationships.A system of degrees and removes is used to describe the relationship between the two cousins and the ancestor they have in common. The degree (first, second, third cousin, etc.) indicates the minimum number of generations separating either cousin from the common ancestor; the remove (once removed, twice removed, etc.) indicates the number of generations, if any, separating the two cousins from each other.
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Noun
1. a daughter of your brother or sister
(antonym) nephew
(hypernym) kinswoman
(hyponym) great-niece, grandniece

n. niece, daughter of one's brother or sister

(n.)
A relative, in general; especially, a descendant, whether male or female; a granddaughter or a grandson.
  

(n.)
A daughter of one's brother or sister, or of one's brother-in-law or sister-in-law.