copywrite/copyright

I see this one misused all the time, especially among my students when they need to provide a "copywrite" date for a book they've read.

Once my blood pressure approaches normal, I then very calmly explain to them that is the incorrect form.

It has nothing to do with "writing." Whether you're referring to a book, a song, or anything else that has been published, you're referring to the securing of "rights" to that work.

From now on, please refer to it as "copyright," and everyone will be happy. I'm not even sure what "copywrite" would be. It seems to violate some law of physics or something.