cupboard

Cupboard comes from Middle English cuppeborde or cupbord, formed from cup and board — literally a board for holding cups.

By the 16th century the middle /p/ sound had softened into a /b/, giving the pronunciation we use today, even though the older 'cup' spelling stuck around and became standard again from the 18th century onward.

It's built directly from two words still very much in use on their own — cup and board — making it a small fossil of everyday furniture-naming.