# UFO

/ˌjuˌɛˈfoʊ/ (US)

Source: https://englishreference.com/word/ufo
Updated: 2026-08-08

## Senses

### 1. unidentified flying object

noun · CEFR B1

Stands for Unidentified Flying Object. You use this for any object in the sky that cannot be identified, especially one thought to be an alien spaceship.

For teachers: Abbreviation for Unidentified Flying Object. The term is used technically for any unexplained aerial sighting, though in general register it typically implies an extraterrestrial craft.

- The pilot reported seeing a strange silver UFO hovering near the clouds.
- Declassified documents revealed that many reported UFO sightings during the Cold War were actually secret military test flights.

### 2. unfinished craft project

noun · CEFR C2 · Informal · Slang

A project, like a sweater you are knitting, that you started a long time ago but never finished.

For teachers: An acronym for 'Unfinished Object'. Used within hobbyist communities, particularly knitting and quilting, to refer to projects that have been abandoned or left incomplete.

- I have a basket full of UFOs that I really need to finish this winter.
- The veteran quilter admitted to having dozens of UFOs tucked away in her studio, some dating back nearly a decade.

Usage: Commonly used as a countable noun within specific crafting subcultures.

## Examples

- The pilot reported seeing a bright UFO over the desert.
- Local residents gathered to watch the strange lights, convinced they had finally spotted a UFO.
- While most UFO sightings are eventually attributed to weather balloons or military aircraft, a small percentage of cases remain unexplained by conventional atmospheric science.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.