-ology
Meaning of -ology: The branch of knowledge, not the person: one ending names the field and a slightly longer one names its practitioner.
Definition of -ology
The suffix -ology names a field of study or a branch of medicine devoted to whatever the root identifies. Cardiology is the study of the heart, dermatology of the skin, neurology of the nervous system. The ending is properly just -logy, since the o in front of it belongs to the combining form of the root rather than to the suffix.
What does the ending name?
A body of knowledge and the clinical service built on it. In hospital use the word usually means both at once, so a referral to cardiology sends a patient to a department rather than to a subject. The root decides the boundary of the field, and roots are drawn from organs, tissues, substances and processes alike. That is why some fields are defined by an organ, some by a type of tissue found throughout the body, and some by a kind of disease that crosses every organ. Cardiology takes an organ, hematology takes a tissue that reaches everywhere, and oncology takes a disease process wherever it arises.
How is the practitioner's title formed?
By exchanging the ending for one naming a person, so the field ending is replaced by an ending meaning one who studies. The pattern is regular enough to predict in either direction, and a reader meeting an unfamiliar specialty can usually work out the title that goes with it.
| Field | What it covers | Practitioner |
|---|---|---|
| cardiology | the heart | cardiologist |
| dermatology | the skin | dermatologist |
| endocrinology | the hormone glands | endocrinologist |
| nephrology | the kidneys | nephrologist |
| hematology | the blood | hematologist |
Which fields break the pattern?
Several, and the exceptions are worth knowing because they are common. Pathology and oncology take their roots from disease and from a swelling rather than from any body part. Psychiatry, pediatrics and obstetrics use entirely different endings, so no practitioner title in those fields ends in the usual way. Lung medicine is the most confusing case, since pulmonology, respiratory medicine and chest medicine all name the same work, and a pulmonary specialist is the same doctor under a fourth label. Titles such as dermatologist and endocrinologist follow the regular rule exactly.
Terms built on -ology
16 entries in this glossary use this word part. Each one follows the same pattern.
- assistive technology Any device or technology that helps a disabled person.
- cytology Cytology is the microscopic examination of individual cells, commonly used to screen for…
- epidemiology Counting cases, comparing exposed and unexposed groups, and testing whether an…
- etiology Diagnosis names what a condition is; etiology names what produced it, and the two answers…
- histology Architecture is the point: how cells sit relative to one another often says more than how…
- histopathology The study of diseased cells and tissues using a microscope.
- immunology Immunology is the scientific study of the immune system, including how it defends against…
- methodology The section readers skip is the one that decides whether the result at the end of the…
- morphology Shape treated as evidence: what a cell, an organ or a whole organism looks like, before…
- nanotechnology Nanotechnology engineers materials at the scale of individual atoms and molecules, with…
- neuropsychology A scan shows structure, while neuropsychological testing shows what a person can actually…
- oncology One word covering hundreds of separate diseases, oncology holds together because the…
- pharmacology Pharmacology is the scientific study of how drugs interact with the body, covering their…
- radiology The name says radiation, yet several of the field's most used methods, ultrasound and…
- sputum cytology Examination under a microscope of cells found in sputum (mucus and other matter brought…
- toxicology Toxicology examines how chemicals and other substances harm the body, guiding the…
Also known as
Used in a sentence
The suffix -ology at the end of the term identified it as a branch of medicine.
Good to know
The ending names the field while a longer ending names the person, so cardiology is the specialty and cardiologist is the doctor, and a handful of fields such as psychiatry follow neither pattern.
Word origin
Where “-ology” comes from
From the Greek logos, meaning word, reason or an account of something; the linking o so often seen in front of it is supplied by the root, not by the suffix.