noun
one-length haircut; uniform-length cut
A hairstyle where all the hair is cut to the same length, without layers. Often associated with a straight, blunt cut. Wasei-eigo from English 'one-length'.
wasei-eigo (Japanese-coined English), from one-length
彼女は髪をワンレングスに切ってもらった。
She had her hair cut into a one-length style.
ワンレングスのボブが今年のトレンドだ。
The one-length bob is trendy this year.