noun, noun which may take the genitive case particle 'no'
Used to indicate the first item or person in an ordered sequence. Often followed by の to modify a noun.
一番目の角を右に曲がってください。
Please turn right at the first corner.
彼はクラスで一番目の成績だった。
He had the top grades in the class.
Compound of 一番 (いちばん, 'number one') + 目 (め, ordinal suffix).