red dwarf

WordReference Random House Unabridged Dictionary of American English © 2026

red′ dwarf′, [Astron.]

1. Astronomy any of the faint reddish stars having diameters about half that of the sun and low surface temperatures, about 2000–3000 K;
   a main sequence star of spectral type M.

• 1915–20

Collins Concise English Dictionary © HarperCollins Publishers::

red dwarf noun

1. one of a class of small cool main-sequence stars