dotted line; perforated line
Refers to a line made of dots or dashes, often used in diagrams, forms, or for cutting guides.
点線に沿って切ってください。
Please cut along the dotted line.
地図の点線は県境を示している。
The dotted line on the map indicates the prefectural border.
I drew a dotted line on the diagram to show the boundary.
Please cut along the dotted line to use this ticket.
Please cut with scissors following the dotted line.
I highlighted the important part by enclosing it with a dotted line.