The Collaborative International Dictionary of English v.0.48:

Revetment \Re*vet"ment\, n. [F. rev[^e]tement the lining of a
   ditch, fr. rev[^e]tir to clothe, L. revestire. See Revest,
   v. t.] (Fort. & Engin.)
   A facing of wood, stone, or any other material, to sustain an
   embankment when it receives a slope steeper than the natural
   slope; also, a retaining wall. [Written also
   rev[^e]tement.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

revetment
    n 1: a barrier against explosives
    2: a facing (usually masonry) that supports an embankment [syn:
       revetment, revetement, stone facing]