spectral type


Definition of spectral type

: the type of a star described primarily according to its surface temperature by means of alphabetic categories (such as O, B, A, F, G, K, and M), decimal subdivisions of the categories, and sometimes symbols indicating special characteristics (such as e for stars with bright emission lines, d for dwarfs, and g for giants) Our Sun is classified as a spectral type G2.

Note: Historically, these classes were based on the spectral lines of stars as observed by astronomers. Over time the classes were rearranged according to temperature instead of spectrum, taking them out of their former alphabetic order, but scientists kept using the term “spectral” to describe the system.

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!

Learn More about spectral type

Statistics for spectral type

Cite this Entry

“Spectral type.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/spectral%20type. Accessed 23 Nov. 2020.

Comments on spectral type

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


Test Your Vocabulary

Great Scrabble Words—A Quiz

  • scrabble tiles that read scrabble quiz
  • Which of the following Q-without-U words means the number five in cards or dice?
Spell It

Can you spell these 10 commonly misspelled words?

Add Diction

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

Love words? Need even more definitions?

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