adjective capable of being exchanged for or replaced by something of equal value.
— synonyms: exchangeable
adjective designed to be changed from one use or form to another.
adjective capable of being changed in substance as if by alchemy.
— synonyms: transformable, translatable, transmutable
noun a car that has top that can be folded or removed.
noun a corporate security (usually bonds or preferred stock) that can be exchanged for another form of security (usually common stock).
— synonyms: convertible_security
noun a sofa that can be converted into a bed.
— synonyms: sofa_bed