1.
front line; forefront; top level
The leading position in a field, profession, or activity. Often used to describe someone who is active at the highest level.
2.
line; boundary; dividing line
A line that separates or divides, especially a moral or social boundary that should not be crossed.
Composed of 一 (one) + 線 (line). Has two primary uses: referring to the leading edge of a field, and to a boundary or dividing line.
Common collocations
- 一線で活躍する: to be active at the forefront
- 一線を退く: to retire from the front line
- 一線を越える: to cross the line
- 一線を画す: to draw a line (between); to distinguish clearly
- 第一線: the front line; the forefront
Usage
The expression 一線を画す is particularly common and means to make a clear distinction or to set oneself apart from others. 一線を越える often has moral or social implications — crossing a boundary that shouldn't be crossed.