EMBANKMENT
embankment
(noun) a long artificial mound of stone or earth; built to hold back water or to support a road or as protection
Source: WordNet® 3.1
Etymology
Noun
embankment (plural embankments)
a long mound of earth, stone, or similar material, usually built for purposes such as to hold back or store water, for protection from weather or enemies, or to support a road or railway.
Source: Wiktionary
Em*bank"ment, n.
1. The act of surrounding or defending with a bank.
2. A structure of earth, gravel, etc., raised to prevent water from
overflowing a level tract of country, to retain water in a reservoir,
or to carry a roadway, etc.
Source: Webster’s Unabridged Dictionary 1913 Edition