adj.
  - (of one or more things) available as another possibility. ▸(of two things) mutually exclusive. 
- relating to activities that depart from or challenge traditional norms.
n.
 one of two or more available possibilities.
Derivative
  
  Usage
  Some traditionalists maintain that, because of the word's origin, you can only have a maximum of two alternatives, and that uses where there are more than two are wrong. Such uses are, however, normal in modern standard English.
  Etymology
  C16: from Fr. alternatif, -ive or med. L. alternativus, from L. alternat-, alternare ‘do by turns’, from alternus ‘every other’, from alter ‘other of two’.