Definitions
1.noun(in plural) Interchangeable things or terms.
2.nounA convertible car: a car with a removable or foldable roof able to convert from a closed to open vehicle and back again.
3.nounA convertible security: a stock, bond, etc. that can be turned into another (usually common stock) under certain set terms.
4.nounA computer able to convert from laptop to tablet and back again.