a suffix occurring in nouns that denote actions, conditions, or states ( hypnosis; leukocytosis; osmosis ), esp. disorders or abnormal states ( chlorosis; neurofibromatosis; tuberculosis ). Cf. -otic .
[ on the model of Gk borrowings ending in Gk -osis, as sklerosis SCLEROSIS, derived orig. from verbs ending in the formative -o- ( -o- in n. derivatives), with the suffix -sis -SIS ]