A [[wave]] whose propagation is [[perpendicular]] to its [[oscillation]].<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> | A [[wave]] whose propagation is [[perpendicular]] to its [[oscillation]].<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> |