Jno.

Jno. is a clerk's shorthand for the given name John. Writers shortened common first names to save time and ink, usually by keeping the first letters and the last one or two, often with the final letters raised above the line.

In rare cases the same letters were used for Jonathan, so if the family had a Jonathan, compare other records. Usually, a record that says Jno. Smith in one place and John Smith in another is naming the same man. When transcribing, keep Jno. as written and add [John] if you want to make it clear.