gland of the abdomen, 1570s, from Latinized form of Greek pankreas "sweetbread (pancreas as food), pancreas," literally "entirely flesh," from pan- "all" (see pan-) + kreas "flesh" (from PIE root *kreue- "raw flesh"), probably so called for the homogeneous substance of the organ. Related: Pancreatic.
word-forming element in medicine denoting "diseases characterized by inflammation" (of the specified part), Modern Latin, from Greek -itis, feminine of adjectival suffix -ites "pertaining to." Feminine because it was used with an implied nosos "disease," a feminine noun; especially in arthritis (nosos) "(disease) of the joints." Arthritis (16c.) was one of the earliest appearances of the suffix in English and from it the suffix was abstracted in other uses.
<a href="https://www.etymonline.com/word/pancreatitis">Etymology of pancreatitis by etymonline</a>
Harper, D. (n.d.). Etymology of pancreatitis. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/pancreatitis