Liberal Dictionary English Dictionary
noun
- civil engineering broken stones loosely deposited in water or on a soft bottom to provide a foundation and protect a riverbed or river banks from scour: used for revetments, embankments, breakwaters, etc
also riprap, “loose stone thrown down in water or soft ground as foundation,” 1822, American English, perhaps connected with earlier nautical word rip-rap meaning “stretch of rippling water” (often caused by underwater elevations), 1660s, probably of imitative origin (cf. riprap “a sharp blow,” 1570s).