Merriam-Webster Logo
SINCE 1828
Menu
dictionary thesaurus

M star

noun

Definition of M star 

: a red star characterized primarily by a surface temperature of 3,000 kelvins or less

— called also Type M star

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

First Known Use of M star

1927, in the meaning defined above

Keep scrolling for more

Learn More about M star

Dictionary Entries near M star

msngr

MSS

MST

M star

MsTh1

MsTh2

mstr

Statistics for M star

Look-up Popularity

Time Traveler for M star

The first known use of M star was in 1927

See more words from the same year

Comments on M star

What made you want to look up M star? Please tell us where you read or heard it (including the quote, if possible).

Show Comments  Hide Comments 

WORD OF THE DAY

milieu

the setting in which something occurs

Get Word of the Day daily email!

Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Citation

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

Ask the Editors

Word Games