Ufo (noun)

A flying object that has not been identified as a known aircraft or natural phenomenon.

Origin:

Abbreviation of "unidentified flying object".

Examples:

1. The witnesses reported seeing a UFO in the night sky.
2. The government denies any knowledge of UFOs.
3. Many people believe that UFOs are evidence of alien life.
4. The UFO was tracked on radar before it disappeared.
5. The UFO sightings caused a stir in the media.