Definition of "Convertible" :

noun: a car that has top that can be folded or removed

noun: a sofa that can be converted into a bed

noun: a corporate security (usually bonds or preferred stock) that can be exchanged for another form of security (usually common stock)

adjective: capable of being changed in substance as if by alchemy

adjective: capable of being exchanged for or replaced by something of equal value

"Convertible securities."

adjective: designed to be changed from one use or form to another

"A convertible sofa."