cast·​mate | \ ˈkast-ˌmāt also ˈkäst- \
plural castmates

Definition of castmate

: a fellow member of a cast of actors I look at some of my castmates and see all the great acting they're doing …— Kristin Bauer van Straten, quoted in Tampa Bay Times, 14 June 2013

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 castmate

1931, in the meaning defined above

Keep scrolling for more

Learn More About castmate

Time Traveler for castmate

Time Traveler

The first known use of castmate was in 1931

See more words from the same year

Dictionary Entries Near castmate



Castner cell

See More Nearby Entries 

Statistics for castmate

Cite this Entry

“Castmate.” Dictionary, Merriam-Webster, Accessed 28 Sep. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon


Test Your Vocabulary

Difficult Spelling Words Quiz

  • alphabet pasta spelling help
  • Which is the correct spelling?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Love words? Need even more definitions?

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