Word.ws English Dictionary

-sis

-sis suffix: forming nouns of action or process.

Suffix

-sis

  1. forming nouns of action or process
    • catharsis, dialysis, diagnosis, crisis
  2. forming nouns of condition
    • psoriasis, sepsis, tuberculosis, psychosis
  3. forming additional nouns
    • basis, oasis, thesis, stasis

Forms of -sis

plural-ses

Origin of -sis

Ultimately from Ancient Greek -σις (-sis, “forms noun of action”), often via Latin or French. Identical in meaning with Latin -entia, English -ing.

Questions about -sis

What does -sis mean?
-sis means forming nouns of action or process.
What part of speech is -sis?
-sis is a suffix.

Words near -sis in the dictionary

  1. -sicles
  2. -side
  3. -sie
  4. -sies
  5. -sion
  6. -sis
  7. -ski
  8. -sky
  9. -slide
  10. -slop
  11. -soc

Source and license

Adapted from Wiktionary: -sis (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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Cite this entry: “-sis.” Word.ws, https://word.ws/-sis. Based on Wiktionary, CC BY-SA 4.0.