4 Roots and Strategies for Decoding Terms

Roots and combining forms

A word root carries a medical term’s central meaning and often names a body part. A combining form is a root joined to a combining vowel, most often o. The vowel helps connect word parts and usually does not contribute meaning of its own.

Common roots and combining forms include:

• cardi, cardi/o: heart; as in cardiology.

• gastr, gastr/o: stomach; as in gastritis.

• enter, enter/o: intestine; as in gastroenteritis.

• neur, neur/o: nerve; as in neurology.

• oste, oste/o: bone; as in osteitis.

• derm, derm/o: skin; as in dermatitis.

• hepat, hepat/o: liver; as in hepatitis.

• nephr, nephr/o: kidney; as in nephrology.

A root’s spelling may change slightly in a complete term. Roots can appear in different positions, and a term can contain more than one root. Not every term has a prefix or a suffix.

A strategy for decoding terms

Use the whole term, rather than assuming that each sequence of letters is a word part in every context. When available, consider the sentence or topic where the term appears.

1. Read the whole term and notice its spelling and context.

2. Look at the end for a suffix. It often identifies a condition, process, procedure, or other feature. For example, -itis means inflammation.

3. Check the beginning for a prefix. It can add information such as location, direction, amount, or degree, though a term may have no prefix.

4. Identify the root or roots that name body parts or systems. Separate a combining vowel from the root when identifying the root itself.

5. Combine the parts into a clear definition. Start with the suffix’s meaning, then apply any prefix and root meanings in a natural phrase.

6. Check whether the interpretation fits the context. If a part or meaning is uncertain, consult a reliable medical dictionary or reference.

This method is a decoding aid, not a substitute for checking an unfamiliar term. Medical terms do not all follow the same simple pattern: they may contain multiple roots and may lack a prefix or suffix.

Worked example: gastroenteritis

In gastroenteritis, -itis means inflammation. The roots are gastr, meaning stomach, and enter, meaning intestine. The o in gastr/o/enter links the roots, giving the meaning “inflammation of the stomach and intestines.” The suffix identifies the kind of condition, while the roots indicate the body parts involved.

Worked example: pericarditis

In pericarditis, -itis means inflammation, peri- means around, and cardi means heart. Together, the parts give the meaning “inflammation of the membrane around the heart.” Confirm the complete medical definition in context or with a trusted reference.