Alternate is a term used in mathematics with several different meanings. (1) Alternate angles are angles on opposite sides and opposite ends of a line that cuts two parallel lines. (2) A well-known theorem called the alternate segment theorem involves the segment on the opposite side of a given chord of a circle. (3) An alternate hypothesis in statistics is the alternative offered to the null hypothesis. (4) To alternate is to cycle backwards and forwards between two different values: e.g. 0, 1, 0, 1, 0, 1 ...