-asis

1.
a suffix occurring in scientific, especially medical, words from Greek:
psoriasis.
Origin
< Latin < Greek -iā- verb stem + -sis -sis
British Dictionary definitions for -asis

-asis

suffix
1.
a variant of -iasis

-iasis

combining form
1.
(in medicine) indicating a diseased condition: psoriasis Compare -osis (sense 2)
Word Origin
from New Latin, from Greek, suffix of action