A guest was a visitor who was welcomed inside another's home, place of business, or some organized event. This usually involved hospitality from the host.
In 2364, Ligonian custom made it clear that a visiting leader became an honored guest. That year when Captain Jean-Luc Picard and Counselor Deanna Troi transported to the surface of Ligon II, they were met by Lutan who told them to consider themselves his honored guests. (TNG: "Code of Honor")