Heart of the matter: Core vs. corps

A whole group of writers seem to misunderstand the significant difference between these two similar-sounding words.

core is the central or most important part of something: The puppet government was corrupt to its core.

corps, however, is a division of military personnel, usually those who have a specialized function: The Marine Corps landed on the beaches shortly before dawn.

A good way to remember this is that corps, because of its s, look like it’s plural, hence a group, while core has no s and so looks like it’s singular, hence a lone, single axis at the center of a larger thing.