noun
Refers to a male child of one's sibling; the female counterpart is 姪. More familiar forms such as 甥っ子 are also common in everyday speech.
週末、甥と公園で遊んだ。
I played at the park with my nephew over the weekend.
甥は今年小学校に入学した。
My nephew started elementary school this year.
The kanji 甥 conventionally represents the meaning 'nephew'; the historical derivation of the Japanese reading おい is not specified.