acra·​sin ə-ˈkrā-sᵊn How to pronounce acrasin (audio)
plural acrasins
: a substance (such as cyclic AMP) that is secreted by myxamoebae of various cellular slime molds (such as those of the genus Dictyostelium or Acrasis) and that functions as a chemotactic agent attracting and causing the aggregation of similar amoeboid cells into a pseudoplasmodium
The cells are not only oriented by … acrasin, but induced to secrete it; they thus relay the orienting signals.B. M. Shaffer, Nature, 12 June 1975

Word History


New Latin Acrasiales acrasiales + -in entry 1

First Known Use

1947, in the meaning defined above

Time Traveler
The first known use of acrasin was in 1947

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!

Dictionary Entries Near acrasin

Cite this Entry

“Acrasin.” Dictionary, Merriam-Webster, Accessed 20 Jun. 2024.

Love words? Need even more definitions?

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