riprap

 
Pronunciation: /ˈrɪprap/
North American

noun

[mass noun]
  • loose stone used to form a foundation for a breakwater or other structure: the rock was used extensively for ballast and riprap [as modifier]: a riprap breakwater

verb (ripraps, riprapping, riprapped)

[with object]
  • strengthen with riprap: incentives to keep landowners from riprapping riverbanks

Origin:

mid 19th century: reduplication of rap1