What was the name in Greek for the god Jono?

The name "Jono" does not correspond to a well-known Greek deity. It is possible that you might be referring to the Roman god "Janus," who is often associated with beginnings, transitions, and doorways. In Greek mythology, Janus doesn't have a direct equivalent, but he may be loosely compared to the Greek gods associated with thresholds and transitions, such as Hermes.