adjective

1. providing or being a choice between two or among more than two things alternative routes
2. designating or of an institution, enterprise, etc. that appeals to unconventional or nontraditional interests an alternative school

Etymology: ML alternativus: see alternate

noun

1. a choice between two or among more than two things
2. either or one of the things to be chosen
3. something remaining to be chosen is there an alternative to going?