The dictionary says that niece means the daughter of your sister, brother, sister-in-law or brother-in-law, but I believe that niece means a lovely cute girl whom I love like my own daughter. – Unknown
By definition, a niece is the daughter of a sister, brother, sister-in-law, or brother-in-law, but this is less relevant for someone who loves their niece with all their heart and sees in her a cute and kind girl who could be their own daughter. A niece is just that girl that is “almost” our daughter.