A "Close Encounter of the First Kind" refers to a type of UFO sighting where a person observes an unidentified flying object at a distance of 150 meters or less. This classification is part of a system developed by J. Allen Hynek, an astronomer who studied UFO phenomena. The encounter typically involves visual sightings without any physical interaction or evidence left behind. This term is one of several categories used to describe encounters with extraterrestrial life or UFOs. Other classifications include the Second Kind, which involves physical evidence, and the Third Kind, which includes sightings of beings or entities.