People reporting unidentified flying object (UFO) sightings describe a variety of shapes and features. The term flying saucer came from a misreporting of Kenneth Arnold’s 1947 account, in which he described crescent shapes moving like saucers skipping on water; a newspaper mistakenly described the objects as saucer-shaped.
Witnesses often describe objects moving unnaturally or suddenly, without making sound, and displaying unusual changes in brightness or color. Visual impressions regarding the distance and speed of UFOs are unreliable, because they are based on an assumed size, often against a blank sky.