http://en.wikipedia.org/wiki/Question_mark According to the wikipedia article I've linked to above, "qo" was sometimes used in the middle ages to abbreviate the latin word "questio" in the way that we might use a modern day question mark. I can't find any example of this anywhere online. Help?
The Wikipedia article itself says evidence is lacking:
Citation  is a 19th century dictionary:
I couldn't find this particular edition, but none of the other 19th century editions I found contained this claim.