-sis

Etymology
Ultimately from, often via Latin or French. Identical in meaning with Latin -entia, English -ing.

Suffix
(plural )


 * 1) forming nouns of action or process
 * catharsis, dialysis, diagnosis, crisis
 * 1)  forming nouns of condition
 * psoriasis, sepsis, tuberculosis, psychosis
 * 1) forming additional nouns
 * basis, oasis, thesis, stasis

Usage notes
Not very productive: primarily used for borrowed terms from Ancient Greek, though there are also modern coinages based on Ancient Greek roots.