a 'convertible' sofa [=a sofa that converts into a bed]
The bonds are 'convertible' into stock.
a 'convertible' currency
(..) Oh, where'd you go? -To a restaurant. -Arby's. I had the roast beef. So I decided I'm gonna go with a convertible. All right, classic. High-five. Can you tell me where the Xerox machine is? Oh, sure, babe. Salesmen-only copy room right there. (..)1998 TvShow: Seinfeld Title: The Dealership Season: 9 Episode 11