A line is an identifiable path created by a point moving in space. Line is one-dimensional and can vary in width, direction and length.
There are 6 different types of line: Horizontal, Vertical, Diagonal, Curved, Zigzag and Broken/Dashed.
The most common use of line is to show the outline of an object. This type of line is called a contour line. Contour lines show where an object ends.
Image Source: http://thevirtualinstructor.com/line.html
Lines can be used in many different ways. They can show movement, create areas of light and shadow and they can be used to suggest a mood or a feeling within a work of art.
Lines that suggest movement...
Lines that create areas of light and shadow...
Lines can express different moods based on their thickness or thinness, fluidity or rigidness and lightness or darkness.