What did it mean when Jane Austen wrote shire in Pride and Prejudice?

You may be referring to -----shires, or as the 1940 movie has it, "Blankshires."

It was common at the time for authors to wish not to identify people or places that might be real, and use blanks to maintain their anonymity. It was easy to create a fictional town or person, but army regiments were raised in specific large areas such as counties, after which they often were named. Jane Austen did not want to have to create a fictional county, but she also did not want to name a real regiment, so she produced the -----shires as a fictional one.