Capitalization, Titles

Q. When referring to the US Army Corps of Engineers, in saying “the Corps of Engineers” and “the Corps,” how should the shortened forms be capitalized? Should “the Corps of Engineers” be in initial caps and “the corps” be in lowercase?

A. The Chicago Manual of Style includes the following examples among the forty or so listed at paragraph 8.111:

Army Corps of Engineers; the corps

United States (or US) Army; the army

United States Coast Guard; the Coast Guard or the coast guard

United States Marine Corps; the Marine Corps or the marine corps; the US Marines; a marine

United States Navy; the navy

United States Signal Corps; the Signal Corps or the signal corps

The terms “army” and “navy” when used alone are considered to be generic, whereas, for example, the “Army Corps of Engineers” (or “Corps of Engineers”) and the “Marine Corps” are more specialized by virtue of being unique subbranches within the US armed forces. “Coast Guard” and “Signal Corps,” on the same principle, are often capitalized, but any of these may be lowercased if used alone. “Corps” becomes generic when used by itself. (All these terms are routinely capitalized in the military’s own documentation—a matter of institutional pride.)