We invited President Aardvark to dinner.
You capitalize president because it’s his official title and it’s right before his name.
Aardvark, the class president, came to dinner.
President is lowercase because it’s after his name and it’s just descriptive. You’re describing his role instead of using president as his official title.
The president came to dinner.
If there is no name, the title is usually lowercase.
Our class president, Aardvark Blueback, came over for dinner.
Sometimes a title may come directly before the name but still be lowercase because it’s simply describing someone’s role.
Colonel Mustard killed Mr. Boddy.
Professor Diggs, of the Archeology Department, is looking for Atlantis.
Mr. Waters, vice president of operations, will make an announcement today.
Mrs. Butterworth, the chairwoman of Pancakes Anonymous, is retiring.
The managing editor, Will Writealot, got fired.
Can you name all the US presidents?
My kids have all the books written by Dr. Seuss.