An oblique line segment is a slanted or diagonal line segment. It is not perpendicular or parallel, nor does it make a right angle with a given plane or surface.
A line is infinite, but a line segment is a part of a line with two endpoints. This type of line segment intersects a given plane or surface at an angle other than 90 degrees. Its slope is also not equal to zero. There are four other types of line segments: parallel, perpendicular, vertical and horizontal. If a line segment does not fit into one of these four categories, then it is usually oblique.