Outer wall
Shield and outer wall are semantically related. In some cases you can use "Shield" instead a noun phrase "Outer wall".
Shield
Shield noun - Means or method of defending.
Cite this Source
Shield and Outer wall. (2016). Retrieved 2026, August 14, from https://thesaurus.plus/related/outer_wall/shield
Outer wall & Shield. N.p., 2016. Web. 14 Aug. 2026. <https://thesaurus.plus/related/outer_wall/shield>.
Shield or Outer wall. 2016. Accessed August 14, 2026. https://thesaurus.plus/related/outer_wall/shield.
Google Ngram Viewer shows how "outer wall" and "shield" have occurred on timeline