a Not traditional, outside the mainstream, underground (e.g., (term|alternative medicine|lang=en), (term|alternative lifestyle|lang=en), (w|alternative rock)).
n A situation which allows a mutually exclusive choice between two or more possibilities; a choice between two or more possibilities. (defdate|from 17th c.)
n The remaining option; something available after other possibilities have been exhausted. (defdate|from 18th c.)