# comet

/ˈkɑmət/ (US) · /kˈɒmɪt/ (UK)

Source: https://englishreference.com/word/comet
Updated: 2026-06-20

## Senses

### 1. astronomy

noun · CEFR B2

a ball of ice and dust in space that has a long tail of light when it moves near the sun.

For teachers: a small solar system body that orbits the sun and, when close enough, displays a visible atmosphere or tail due to the effects of solar radiation.

- The comet was visible in the night sky for several weeks as it passed the earth.
- Halley's Comet is perhaps the most famous periodic visitor to our inner solar system, returning to the vicinity of Earth every seventy-five years.

Usage: Often used with the verbs 'orbit', 'appear', or 'pass'.

### 2. computing

noun · CEFR C2 · Technical

a way for a web server to send information to a browser immediately without waiting for a request.

For teachers: a web application model where a long-held HTTP request allows a server to push data to a client browser.

- The developer used a comet approach to make the chat app update in real time.
- Before the widespread adoption of WebSockets, Comet was a common technique for achieving low-latency communication between the server and the browser.

Usage: Usually treated as an uncountable technical concept or a specific architectural pattern.

## Examples

- The comet is visible in the night sky this week.
- Astronomers used high-powered telescopes to track the comet as it approached the inner solar system.
- Unlike planets which follow nearly circular paths, a comet typically travels on a highly elliptical orbit, spending most of its existence in the freezing outer reaches of the solar system.

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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.