Corps and core are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Corps is a noun. It’s a collective term for all the people making up an organization, typically a military one. For example, the Army Corps of Engineers, or the Marine Corps. Though it looks like a plural word, Corps is said “Cohr” like the final two letters aren’t there.
Core has multiple meanings.
- As a verb, it means to remove the seeded center of an apple or pear.
- As a noun, it means the center or heart of a fruit or other multi-layer, round object.
- As a noun in a figurative sense, it can mean the main concept or idea of a subject.
The following story uses both words correctly:
Cornelius was an excellent student and athlete, but at his core, he knew he was meant to serve in the US Marine Corps.