Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Parallelism is a term in geometry and in everyday life that refers to a property in Euclidean space of two or more lines or planes, or a combination of these. The existence and properties of parallel lines are the basis of Euclid''s parallel postulate. Two lines in a plane that do not intersect or meet are called parallel lines.In the Unicode character set, the ''parallel'' and ''not parallel'' signs have codepoints U+2225 ( ) and U+2226 ( ) respectively. They are part of the Mathematical Operators range.