radio astronomy

WordReference Random House Unabridged Dictionary of American English © 2025

ra′dio astron′omy, 

1. Astronomy the branch of astronomy that utilizes extraterrestrial radiation in radio wavelengths rather than visible light for the study of the universe.

• 1945–50

Collins Concise English Dictionary © HarperCollins Publishers::

radio astronomy noun

1. a branch of astronomy in which a radio telescope is used to detect and analyse radio signals received on earth from radio sources in space