val·la·tion 
(vă-lāshən)
(vă-lāshən)n.
1. An earthwork wall used for military defense; a rampart.
2. The process of planning or erecting earth fortifications.
[Late Latin vallātiō, vallātiōn-, from Latin vallātus, past participle of vallāre, to surround with a rampart, from vallum, rampart, from vallus, stake.]
valla·to′ry (vălə-tôr′ē) adj.