It's a new word in my vocabulary.
My pursuit of discovery as to the meaning of this word began with a mention of "German gymnasts" in one of Roberta and Hurley Hagood's history stories.
The term Turnverein denotes a gymnastic or athletic club, and Hannibal had one in the mid 1870s. It was located on Hill Street, just east of the intersection with North Main Street.
I have challenged Steve Chou with the task of finding a local photo, but in the meantime, I found this old photo online of a turnverein hall in Milwaukee.
The German word turnverein was Americanized to Turner, and the local hall was called the Turner Hall.