rip-rap or riprap /ripˈrap/

1. Loose broken stones, used to form a foundation on soft ground or under water, or in the construction of revetments and embankments
2. A foundation formed of these

• penny-farthing
• penny-farthings
• penny-fee
• penny-fees
• penny gaff
• penny gaffs
• penny-in-the-slot
• pennyland
• pennylands
• penny loafer
• penny loafers
• penny mail
• penny mails
• penny-piece
• penny-pieces
• penny-pig
• penny-pigs
• penny-pinch
• penny-pinched
• penny-pinching
• penny-pinchs
• penny-plain
• penny-post
• penny-rent
• pennyroyal