-osis
An abnormal condition or process — without the inflammation that -itis implies.
What it means
An abnormal condition, state or process — without implying inflammation.
- Fibrosis — scarring
- Stenosis — narrowing
- Osteoporosis — porous, thinned bone
- Thrombosis — a clot forming
- Diverticulosis — having diverticula, without inflammation
The -osis versus -itis distinction can matter a great deal. Diverticulosis means the pouches are simply present; diverticulitis means one is inflamed. The same word family, two very different situations.
In practice
Across letters and reports of every specialty.
"-opathy" is a close relative, meaning disease or disorder of something — as in neuropathy or retinopathy.
Why it matters
Check which ending you have been given. Where both exist — as with diverticulosis and diverticulitis — they mean different things and are managed differently.
Ask whether it needs treatment or simply describes a state. Many -osis findings, particularly incidental ones, need nothing at all.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026