1. A choice limited to one of two or more possibilities, as of things, propositions, or courses of action, the selection of which precludes any other possibility: You have the alternative of riding or walking.
2. One of the things, propositions, or courses of action that can be chosen: The alternative to riding is walking.
3. A possible or remaining course or choice: There was no alternative but to walk.
4. Affording a choice of two or more things, propositions, or courses of action.
5. (Of two things, propositions, or courses) mutually exclusive so that if one is chosen the other must be rejected: The alternative possibilities are neutrality and war.
6. Employing or following nontraditional or unconventional ideas, methods, etc.; existing outside the establishment: an alternative newspaper; alternative lifestyles.
7. Logic. (of a proposition) asserting two or more choices, at least one of which is true.