They are lines that intersect at 90 degrees
No. Parallel lines do not intersect; perpendicular lines intersect at 90 degrees
They are lines that intersect one another at 90 degree angles.
Perpendicular lines intersect at right angles which is 90 degrees
Perpendicular lines are lines that intersect at a right angle (90 degrees).
In two dimensional space they must. In three (or more) dimensions they need not.
Pair of lies crossing at right angles at the origin.
Not necessarily. Consider two lines that intersect at some angle other than 90 degrees. Then the angle of intersection is not 90 degrees means they are not perpendicular. But, because they intersect, neither are they parallel.
2 lines that do not and will not intersect are called parallel lines.
Any 2 lines can intersect providing that they are not parallel lines
Parallel straight lines never intersect.
If the 2 lines lie in the same plane, and they are not parallel, then they will intersect at some point. If the 2 lines are skew lines, then they are not in the same plane, and they will not intersect (but they are Not Parallel)