Non-Euclidean geometry
two geometries based on axioms closely related to those specifying Euclidean geometry / From Wikipedia, the free encyclopedia
Non-Euclidean geometry is a type of geometry. Non-Euclidean geometry only uses some of the "postulates" (assumptions) that Euclidean geometry is based on. In normal geometry, parallel lines can never meet. In non-Euclidean geometry they can meet, either infinitely many times (elliptic geometry), or never (hyperbolic geometry).
An example of Non-Euclidian geometry can be seen by drawing lines on a ball or other round object, straight lines that are parallel at the equator can meet at the poles.