Copyright "Notice"

Under current law and pursuant to treaties, etc. in the vast majority of countries, no formalities exist for your "copyright" to attach at the moment of creation/fixation.

BUT it makes enormous sense to label - put a "notice" of copyright - on your work.
Your creative expression is, practically speaking, incomplete, until you also express how *you* exercise your rights respecting reproduction and derivative works.

So, DO Use the word "copyright."

And DO a bit MORE:
Using the word or the "©" symbol, while it does put people on notice that you own and mean to defend the rights to your creation, does not gain the level of extra protection many people think it does. To step up your protection, you must also register your copyright.