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

• squabbles
• squabbling
• rubidiums
• rubidium-strontium dating
• rubied
• rubier
• rubies
• rubiest
• rubified
• rubify
• rubifying
• rubiginose
• rubiginous
• Rubik's Cube
• rub in
• rubin
• rubine
• rubineous
• rubines
• rubins
• rubious
• ruble
• rubles
• rub off on
• rub off on to