"Jno" is an abbreviation for "John". That is it's "official" or "theoretical" meaning. The abbreviation is said to have actually come into English usage based more on the Latin name "Johannes" rather than on the spelling of the English name "John". The clerks followed the convention because they knew that was what it meant and the question of using an abbreviation which was only one letter shorter than the word it represented, was not an issue with them as to change it would have caused confusion. So when you find it in court documents, give the clerk the benefit of the doubt that he knew what he was doing and consider it to be "John". However, always be aware that there is a possibility that a man named "Jonathan" may have been going by a nickname of "Jon", as we would probably spell it today, and that the clerk mistakenly spelled it "John" and abbreviated it in that manner. This situation can only be sorted out by collecting as much information as possible, any all references to both John and Jonathan, and then making a determination to see if they might be the same person. Renee L. Dauven