Like Archie said only 8 grades are needed. A lot of dealers want to 'customize' the system and use terms like "crispy & extra crispy" but that ain't the scale. (It does work well for fried chicken )
Below is the reference scale that is accepted globaly by collectors between collectors. In the glass case in a retail shop, I have seen lots of cute words used to 'cloak' the grade.

Here it is right out of the book....(coins may be different, this is for paper)