Definition:

1. Relating to astronomy, the study of celestial objects and phenomena.

* Example: The astronomer made an astronomical discovery.

2. Of or relating to stars, planets, and other celestial bodies.

* Example: The telescope allowed him to observe astronomical objects.

3. Extremely large or vast in size or amount.

* Example: The project incurred astronomical costs.

4. Highly improbable or unlikely.

* Example: It's astronomical that she won the lottery.

Origin:

The word "astronomical" comes from the Greek words "astron" (star) and "nomos" (law), meaning "the law of the stars."

Usage:

The term "astronomical" is used in both scientific and everyday contexts. In scientific contexts, it refers to the study of astronomy and celestial objects. In everyday language, it is used to describe things that are extremely large, vast, or unlikely.

Synonyms:

* Cosmic

* Celestial

* Starry

* Immense

* Huge

* Enormous

* Vast

* Incredible

* Unbelievable

Antonyms:

* Tiny

* Small

* Minuscule

* Likely

* Probable