Any line means that when any line that meets the requirements has a corresponding relationship with any line, it means that this relationship is applicable to all lines with the same requirements.
For example, the straight line L is perpendicular to any straight line in the plane.
The condition at this time is that the relationships in the plane are perpendicular to each other, and L is equivalent to being perpendicular to all the straight lines in the plane.
Just because the straight line L is perpendicular to countless straight lines in the plane does not mean that the straight line L is perpendicular to all the straight lines in the plane. It can refer to countless parallel straight lines, but it does not represent all straight lines.