cunette

plural cunettes

1. governmentA trench dug in a moat to allow for drainage, or as an extra obstacle for attackers.

   Ford's Ravelin.—Completed in its ditch, ſluices, cunette, aqueducts, ſcarp, and counterſcarp walls; […]

   1773, “Progress and State of the Works beyond the Great Ditch”, in Further Report (being the Eighth) from the Committee of Secrecy Appointed by the House of Commons, Assembled in Westminster in the Sixth Session of the Thirteenth Parliament of Great Britain, to Enquire into the State of the East India Company, London: Sold by T[homas] Evans, at No. 54, in Pater-noster Row; and W. Davis, the corner of Sackville-Street, Piccadilly, →OCLC, page 234

   2 more examples

   Nor was anything done at San Pablo except the cutting of two cunettes necessary for working with heavy machinery, and the projection of a plane for a passage under the Panama Railway, by which the excavations made at K. 35.700 could be carried to the banks of the Chagres.

   1889, Charles Rogers, Intelligence Report of the Panama Canal (50th Congress, 1st session, 1887–1888; House; Miscellaneous Document), Washington, D.C.: United States Government Printing Office, →OCLC, page 11

   In principle, cunettes are carried out with a view to substituting poor load bearing and highly compressible strata with sand with a view to a) reducing residual settlements and b) improving stability.

   1996, Centre for Civil Engineering Research and Codes, “Construction Methods”, in Building on Soft Soils: Design and Construction of Earthstructures both on and into Highly Compressible Subsoils of Low Bearing Capacity, Rotterdam; Brookfield, Vt.: A[ugust] A[imé] Balkema, →ISBN, page 164