Unknown symbol

I typed a list of names in an Excel worksheet followed by city and state. All were typed in capital letters.  When I went back in the file today, the cities are no longer in capital letters.  They now have a symbol in front of them and are in lower case letters.  When I put my cursor on the symbol, it says Show Card. When I click on it, it gives information about the city.  How do I remove this?  I didn't intentionally put it in and don't want it.