-osis

1.
a suffix occurring in nouns that denote actions, conditions, or states (hypnosis; leukocytosis; osmosis), especially disorders or abnormal states (chlorosis; neurofibromatosis; tuberculosis).
Compare -otic.
Origin
on the model of Greek borrowings ending in Greek -ōsis, as sklērōsis sclerosis, derived orig. from verbs ending in the formative -o- (-ō- in noun derivatives), with the suffix -sis -sis
British Dictionary definitions for -osis

-osis

suffix
1.
indicating a process or state: metamorphosis
2.
indicating a diseased condition: tuberculosis Compare -iasis
3.
indicating the formation or development of something: fibrosis
Word Origin
from Greek, suffix used to form nouns from verbs with infinitives in -oein or -oun
Word Origin and History for -osis

word-forming element expressing state or condition, in medical terminology denoting "a state of disease," from Latin -osis and directly from Greek -osis, formed from the aorist of verbs ending in -o. It corresponds to Latin -atio.

-osis in Medicine

-osis suff.

  1. Condition; process; action: osmosis.

  2. Diseased or abnormal condition: neurosis.

  3. Increase; formation: leukocytosis.

-osis in Science
-osis  

  1. A suffix that means:

  2. Diseased condition, as in tuberculosis.

  3. Condition or process, as in osmosis.