astronomical

adjective

as·​tro·​nom·​i·​cal ˌa-strə-ˈnä-mi-kəl 

variants or less commonly astronomic

ˌa-strə-ˈnä-mik 

1

: of or relating to astronomy

astronomical observations

2

: enormously or inconceivably large or great

astronomical numbers

an astronomical price

astronomically

ˌa-strə-ˈnä-mi-k(ə-)lē 

adverb

Synonyms of astronomical

• huge
• enormous
• vast
• tremendous
• gigantic
• massive
• giant
• colossal
• monumental
• immense
• mammoth
• bumper
• titanic
• mountainous
• cosmic
• planetary
• monstrous

Examples of astronomical in a Sentence

The cost of the office building was astronomical.

We got an astronomical telephone bill this month.

Recent Examples on the Web

By Friday, the first day of (astronomical) spring, temperatures will settle into the mid and upper 50s by the middle of the afternoon. —Cutter Martin, CBS News, 17 Mar. 2026

Researchers are excited about gravitational waves because these spacetime ripples constitute an entirely new way to study the universe, independent of the electromagnetic radiation (light) upon which most other astronomical observations rely. —K. R. Callaway, Scientific American, 17 Mar. 2026

Beyond rock and ice The finding of L 98-59 d challenges the long-standing astronomical belief that small exoplanets must be either gas dwarfs or water worlds covered in ice and oceans. —Mrigakshi Dixit, Interesting Engineering, 16 Mar. 2026

The wild weather has had widespread effects on transportation and power supplies across the Midwest, and the heavy snow and cold are forecast to push into areas that depend heavily on natural gas for heating, raising fuel demand days before the official arrival of astronomical spring. —Bloomberg, Mercury News, 16 Mar. 2026

Word History

Etymology

Late Latin astronomicus "of or relating to astronomy" (borrowed from Greek astronomikós "of astronomy, skilled in astronomy," from astronomía astronomy + -ikos -ic entry 1) + -al entry 1

First Known Use

1551, in the meaning defined at sense 1

Phrases Containing astronomical

• astronomical unit

Rhymes for astronomical

• anatomical
• economical
• comical
• neuroanatomical
• uneconomical

Kids Definition

astronomical

adjective

as·​tro·​nom·​i·​cal ˌas-trə-ˈnäm-i-kəl 

variants also astronomic

-ˈnäm-ik 

1

: of or relating to astronomy

2

: extremely or unbelievably large

the cost was astronomical

astronomically

-ˈnäm-i-k(ə-)lē 

adverb